645421568 has 40 divisors (see below), whose sum is σ = 1406829600. Its totient is φ = 293370880.

The previous prime is 645421523. The next prime is 645421577. The reversal of 645421568 is 865124546.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51668 + ... + 62931.

It is an arithmetic number, because the mean of its divisors is an integer number (35170740).

Almost surely, 2^645421568 is an apocalyptic number.

It is an amenable number.

645421568 is an abundant number, since it is smaller than the sum of its proper divisors (761408032).

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

645421568 is a wasteful number, since it uses less digits than its factorization.

645421568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114628 (or 114612 counting only the distinct ones).

The product of its digits is 230400, while the sum is 41.

The square root of 645421568 is about 25405.1484545948. The cubic root of 645421568 is about 864.2004564606.

The spelling of 645421568 in words is "six hundred forty-five million, four hundred twenty-one thousand, five hundred sixty-eight".