125664561 has 32 divisors (see below), whose sum is σ = 215049600. Its totient is φ = 71677440.

The previous prime is 125664541. The next prime is 125664577. The reversal of 125664561 is 165466521.

125664561 is a `hidden beast` number, since 1 + 2 + 5 + 6 + 645 + 6 + 1 = 666.

It is not a de Polignac number, because 125664561 - 2²² = 121470257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (125664541) 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, 7396 + ... + 17493.

It is an arithmetic number, because the mean of its divisors is an integer number (6720300).

Almost surely, 2^125664561 is an apocalyptic number.

125664561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

125664561 is a deficient number, since it is larger than the sum of its proper divisors (89385039).

125664561 is a wasteful number, since it uses less digits than its factorization.

125664561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24926 (or 24920 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 125664561 is about 11210.0205619794. The cubic root of 125664561 is about 500.8845156747.

The spelling of 125664561 in words is "one hundred twenty-five million, six hundred sixty-four thousand, five hundred sixty-one".