21999925 has 12 divisors (see below), whose sum is σ = 28160896. Its totient is φ = 17031600.

The previous prime is 21999917. The next prime is 21999973. The reversal of 21999925 is 52999912.

It is not a de Polignac number, because 21999925 - 2³ = 21999917 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13419 + ... + 14968.

Almost surely, 2^21999925 is an apocalyptic number.

21999925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21999925 is a deficient number, since it is larger than the sum of its proper divisors (6160971).

21999925 is a wasteful number, since it uses less digits than its factorization.

21999925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28428 (or 28423 counting only the distinct ones).

The product of its digits is 131220, while the sum is 46.

The square root of 21999925 is about 4690.4077647898. The cubic root of 21999925 is about 280.2036146516.

The spelling of 21999925 in words is "twenty-one million, nine hundred ninety-nine thousand, nine hundred twenty-five".