645601968 has 80 divisors (see below), whose sum is σ = 2021596800. Its totient is φ = 195635520.

The previous prime is 645601967. The next prime is 645601993. The reversal of 645601968 is 869106546.

645601968 is a `hidden beast` number, since 6 + 456 + 0 + 196 + 8 = 666.

645601968 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 (645601967) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63178 + ... + 72681.

It is an arithmetic number, because the mean of its divisors is an integer number (25269960).

Almost surely, 2^645601968 is an apocalyptic number.

It is an amenable number.

645601968 is an abundant number, since it is smaller than the sum of its proper divisors (1375994832).

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

645601968 is a wasteful number, since it uses less digits than its factorization.

645601968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135887 (or 135875 counting only the distinct ones).

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

The square root of 645601968 is about 25408.6986679759. The cubic root of 645601968 is about 864.2809657211.

The spelling of 645601968 in words is "six hundred forty-five million, six hundred one thousand, nine hundred sixty-eight".