656565978 has 16 divisors (see below), whose sum is σ = 1315496160. Its totient is φ = 218461296.

The previous prime is 656565971. The next prime is 656565989. The reversal of 656565978 is 879565656.

656565978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (656565971) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 94888 + ... + 101571.

It is an arithmetic number, because the mean of its divisors is an integer number (82218510).

Almost surely, 2^656565978 is an apocalyptic number.

656565978 is an abundant number, since it is smaller than the sum of its proper divisors (658930182).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

656565978 is a wasteful number, since it uses less digits than its factorization.

656565978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197021.

The product of its digits is 13608000, while the sum is 57.

The square root of 656565978 is about 25623.5434317738. The cubic root of 656565978 is about 869.1461115979.

The spelling of 656565978 in words is "six hundred fifty-six million, five hundred sixty-five thousand, nine hundred seventy-eight".