21365925 has 24 divisors (see below), whose sum is σ = 40372416. Its totient is φ = 9767040.

The previous prime is 21365917. The next prime is 21365933. The reversal of 21365925 is 52956312.

It is an interprime number because it is at equal distance from previous prime (21365917) and next prime (21365933).

It is not a de Polignac number, because 21365925 - 2³ = 21365917 is a prime.

It is a super-2 number, since 2×21365925² = 913005502211250, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19824 + ... + 20873.

It is an arithmetic number, because the mean of its divisors is an integer number (1682184).

Almost surely, 2^21365925 is an apocalyptic number.

21365925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21365925 is a deficient number, since it is larger than the sum of its proper divisors (19006491).

21365925 is a wasteful number, since it uses less digits than its factorization.

21365925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40717 (or 40712 counting only the distinct ones).

The product of its digits is 16200, while the sum is 33.

The square root of 21365925 is about 4622.3289584364. The cubic root of 21365925 is about 277.4856741245.

The spelling of 21365925 in words is "twenty-one million, three hundred sixty-five thousand, nine hundred twenty-five".