21065825 has 12 divisors (see below), whose sum is σ = 28496688. Its totient is φ = 15320400.

The previous prime is 21065819. The next prime is 21065831. The reversal of 21065825 is 52856012.

It is an interprime number because it is at equal distance from previous prime (21065819) and next prime (21065831).

It is not a de Polignac number, because 21065825 - 2⁴ = 21065809 is a prime.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

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, 38027 + ... + 38576.

It is an arithmetic number, because the mean of its divisors is an integer number (2374724).

Almost surely, 2^21065825 is an apocalyptic number.

21065825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21065825 is a deficient number, since it is larger than the sum of its proper divisors (7430863).

21065825 is a wasteful number, since it uses less digits than its factorization.

21065825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76624 (or 76619 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 29.

The square root of 21065825 is about 4589.7521719587. The cubic root of 21065825 is about 276.1803807556.

The spelling of 21065825 in words is "twenty-one million, sixty-five thousand, eight hundred twenty-five".