125640621 has 12 divisors (see below), whose sum is σ = 182276380. Its totient is φ = 83393280.

The previous prime is 125640617. The next prime is 125640629. The reversal of 125640621 is 126046521.

125640621 is a `hidden beast` number, since 1 + 256 + 406 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 50211396 + 75429225 = 7086^2 + 8685^2 .

It is not a de Polignac number, because 125640621 - 2² = 125640617 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (125640629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28420 + ... + 32541.

Almost surely, 2^125640621 is an apocalyptic number.

It is an amenable number.

125640621 is a deficient number, since it is larger than the sum of its proper divisors (56635759).

125640621 is a wasteful number, since it uses less digits than its factorization.

125640621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61196 (or 61193 counting only the distinct ones).

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

The square root of 125640621 is about 11208.9527164673. The cubic root of 125640621 is about 500.8527062906.

The spelling of 125640621 in words is "one hundred twenty-five million, six hundred forty thousand, six hundred twenty-one".