21906625 has 48 divisors (see below), whose sum is σ = 31859568. Its totient is φ = 14976000.

The previous prime is 21906617. The next prime is 21906631. The reversal of 21906625 is 52660912.

It can be written as a sum of positive squares in 24 ways, for example, as 19114384 + 2792241 = 4372^2 + 1671^2 .

It is not a de Polignac number, because 21906625 - 2³ = 21906617 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 359095 + ... + 359155.

It is an arithmetic number, because the mean of its divisors is an integer number (663741).

Almost surely, 2^21906625 is an apocalyptic number.

21906625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21906625 is a deficient number, since it is larger than the sum of its proper divisors (9952943).

21906625 is a wasteful number, since it uses less digits than its factorization.

21906625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 21906625 is about 4680.4513671226. The cubic root of 21906625 is about 279.8069460056.

The spelling of 21906625 in words is "twenty-one million, nine hundred six thousand, six hundred twenty-five".