21625660 has 36 divisors (see below), whose sum is σ = 52830792. Its totient is φ = 7414176.

The previous prime is 21625633. The next prime is 21625661. The reversal of 21625660 is 6652612.

21625660 is nontrivially palindromic in base 13.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21625661) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10054 + ... + 12013.

It is an arithmetic number, because the mean of its divisors is an integer number (1467522).

Almost surely, 2^21625660 is an apocalyptic number.

21625660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21625660 is an abundant number, since it is smaller than the sum of its proper divisors (31205132).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21625660 is a wasteful number, since it uses less digits than its factorization.

21625660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22090 (or 22081 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21625660 is about 4650.3397725328. The cubic root of 21625660 is about 278.6055670882.

It can be divided in two parts, 21 and 625660, that added together give a square (625681 = 791²).

The spelling of 21625660 in words is "twenty-one million, six hundred twenty-five thousand, six hundred sixty".