656388009 has 8 divisors (see below), whose sum is σ = 972426720. Its totient is φ = 437591988.

The previous prime is 656387981. The next prime is 656388013. The reversal of 656388009 is 900883656.

656388009 is a `hidden beast` number, since 6 + 5 + 638 + 8 + 0 + 0 + 9 = 666.

It is not a de Polignac number, because 656388009 - 2⁹ = 656387497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (656388049) 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 7 ways as a sum of consecutive naturals, for example, 12155307 + ... + 12155360.

It is an arithmetic number, because the mean of its divisors is an integer number (121553340).

Almost surely, 2^656388009 is an apocalyptic number.

It is an amenable number.

656388009 is a deficient number, since it is larger than the sum of its proper divisors (316038711).

656388009 is a wasteful number, since it uses less digits than its factorization.

656388009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24310676 (or 24310670 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 656388009 is about 25620.0704331585. The cubic root of 656388009 is about 869.0675741533.

The spelling of 656388009 in words is "six hundred fifty-six million, three hundred eighty-eight thousand, nine".