MARK ROBERT NELSON
NPI 1447145644
Counselor - School in Crescent City, CA

NPI Status: Active since June 10, 2025

Contact Information

301 W WASHINGTON BLVD
CRESCENT CITY, CA
ZIP 95531
Phone: (707) 464-6141

NPI Profile Information
Primary Taxonomy
NPI Validation
Other Providers Same Location
Frequently Asked Questions

Individual
Male
Counselor
School

About MARK NELSON

This page provides the complete NPI Profile along with additional information for Mark Nelson, a provider established in Crescent City, California with a medical specialization in Counselor, focusing in school . The healthcare provider is registered in the NPI registry with number 1447145644 assigned on June 2025. The practitioner's primary taxonomy code is 101YS0200X. The provider is registered as an individual and his NPI record was last updated one year ago.

NPI: 1447145644
Provider Name: MARK ROBERT NELSON
Gender: Male
Entity Type: Individual
Location Address: 301 W WASHINGTON BLVD CRESCENT CITY, CA 95531
Location Phone: (707) 464-6141
Mailing Address: 301 W WASHINGTON BLVD CRESCENT CITY, CA 95531
Mailing Phone: (707) 464-6141
Is Sole Proprietor?: No
Enumeration Date: 06-10-2025
Last Update Date: 06-10-2025
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Specialty - Primary Taxonomy

The NPI enumerator requires providers to submit at least one taxonomy code. A taxonomy code is a unique 10-character code that describes the healthcare provider type, classification, and the area of specialization. There could be only one primary taxonomy code per NPI record. For individual NPIs the license data is associated to the taxonomy code.

Classification: Counselor School
Taxonomy Code: 101YS0200X
Type: Behavioral Health & Social Service Providers

NPI NPI Number Validation

How NPI Validation Works

The NPI validation process uses the ISO-standard Luhn algorithm, a mathematical "handshake", to ensure that a provider's 10-digit ID is authentic and free of common typing errors.

To verify the NPI 1447145644, we treat the final digit (4) as the Check Digit—the target answer we need to reach. The process begins by taking the first nine digits and adding a constant value of 24, which accounts for the "80840" prefix required for all U.S. health identifiers. We then double every other digit starting from the right and sum the individual digits of those results together. For this specific NPI, that total comes to 66. The final step is to find the difference between that total and the next multiple of ten (70 - 66 = 4).

Digit-by-digit view

Use the first nine digits for the calculation. Starting from the right, double every other digit. The last digit is the check digit and is not part of the calculation.

Pos 1

Doubled → 2

Pos 2

Unchanged

Pos 3

Doubled → 8

Pos 4

Unchanged

Pos 5

Doubled → 2

Pos 6

Unchanged

Pos 7

Doubled → 10 → 1 + 0

Pos 8

Unchanged

Pos 9

Doubled → 8

Check

Target digit

Regular digit Doubled digit Check digit

Step 1: Double every other digit from the right

Starting with the rightmost digit of the first nine digits, double every other value. If doubling creates a two-digit number, add those digits together.

1 → 2 4 → 8 1 → 2 5 → 10 → 1 4 → 8

Step 2: Add all digits plus the NPI constant

Add the transformed values, the unchanged digits, and the constant 24.

2 + 4 + 8 + 7 + 2 + 4 + 1 + 0 + 6 + 8 + 24 = 66

Step 3: Find the amount needed to reach the next multiple of 10

The next multiple of ten after 66 is 70. The difference is the calculated check digit.

70 - 66 = 4

This NPI is valid

The calculated check digit is 4, which matches the last digit of 1447145644.