Harshad

A Harshad number (or Niven number) is a number divisible by the sum of its digits in a given base. In base 10, 12 is Harshad because 1 + 2 = 3 and 12 ÷ 3 = 4.

Key features

• All single-digit numbers are Harshad.
• The concept can be extended to other bases.

Examples:

1, 2, 10, 12, 18, 20

Further reading

• Harshad on Wikipedia
• Harshad on OEIS