21863925 has 72 divisors (see below), whose sum is σ = 41976480. Its totient is φ = 11275200.

The previous prime is 21863923. The next prime is 21863951. The reversal of 21863925 is 52936812.

21863925 is a `hidden beast` number, since 2 + 18 + 639 + 2 + 5 = 666.

It is not a de Polignac number, because 21863925 - 2¹ = 21863923 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21863925.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21863923) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 358395 + ... + 358455.

Almost surely, 2^21863925 is an apocalyptic number.

21863925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21863925 is a deficient number, since it is larger than the sum of its proper divisors (20112555).

21863925 is an equidigital number, since it uses as much as digits as its factorization.

21863925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145 (or 128 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21863925 is about 4675.8876162714. The cubic root of 21863925 is about 279.6250295337.

The spelling of 21863925 in words is "twenty-one million, eight hundred sixty-three thousand, nine hundred twenty-five".