125664021 has 32 divisors (see below), whose sum is σ = 213331200. Its totient is φ = 71616960.

The previous prime is 125664013. The next prime is 125664031. The reversal of 125664021 is 120466521.

125664021 is a `hidden beast` number, since 1 + 256 + 6 + 402 + 1 = 666.

It is not a de Polignac number, because 125664021 - 2³ = 125664013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (125664031) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 101635 + ... + 102863.

It is an arithmetic number, because the mean of its divisors is an integer number (6666600).

Almost surely, 2^125664021 is an apocalyptic number.

It is an amenable number.

125664021 is a deficient number, since it is larger than the sum of its proper divisors (87667179).

125664021 is a wasteful number, since it uses less digits than its factorization.

125664021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1786 (or 1780 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 125664021 is about 11209.9964763598. The cubic root of 125664021 is about 500.8837982143.

The spelling of 125664021 in words is "one hundred twenty-five million, six hundred sixty-four thousand, twenty-one".