21368625 has 16 divisors (see below), whose sum is σ = 35558016. Its totient is φ = 11396400.

The previous prime is 21368617. The next prime is 21368629. The reversal of 21368625 is 52686312.

It is not a de Polignac number, because 21368625 - 2³ = 21368617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21368629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28117 + ... + 28866.

It is an arithmetic number, because the mean of its divisors is an integer number (2222376).

Almost surely, 2^21368625 is an apocalyptic number.

21368625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21368625 is a deficient number, since it is larger than the sum of its proper divisors (14189391).

21368625 is an equidigital number, since it uses as much as digits as its factorization.

21368625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57001 (or 56991 counting only the distinct ones).

The product of its digits is 17280, while the sum is 33.

The square root of 21368625 is about 4622.6210097736. The cubic root of 21368625 is about 277.4973622020.

The spelling of 21368625 in words is "twenty-one million, three hundred sixty-eight thousand, six hundred twenty-five".