21393625 has 16 divisors (see below), whose sum is σ = 29128320. Its totient is φ = 15558000.

The previous prime is 21393623. The next prime is 21393653. The reversal of 21393625 is 52639312.

It is not a de Polignac number, because 21393625 - 2¹ = 21393623 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21393623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6405 + ... + 9154.

It is an arithmetic number, because the mean of its divisors is an integer number (1820520).

Almost surely, 2^21393625 is an apocalyptic number.

21393625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21393625 is a deficient number, since it is larger than the sum of its proper divisors (7734695).

21393625 is a wasteful number, since it uses less digits than its factorization.

21393625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15585 (or 15575 counting only the distinct ones).

The product of its digits is 9720, while the sum is 31.

The square root of 21393625 is about 4625.3243129536. The cubic root of 21393625 is about 277.6055384082.

The spelling of 21393625 in words is "twenty-one million, three hundred ninety-three thousand, six hundred twenty-five".