645565760 has 56 divisors (see below), whose sum is σ = 1756867200. Its totient is φ = 221336064.

The previous prime is 645565699. The next prime is 645565799. The reversal of 645565760 is 67565546.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 141860 + ... + 146339.

Almost surely, 2^645565760 is an apocalyptic number.

It is an amenable number.

645565760 is an abundant number, since it is smaller than the sum of its proper divisors (1111301440).

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

645565760 is a wasteful number, since it uses less digits than its factorization.

645565760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288223 (or 288213 counting only the distinct ones).

The product of its (nonzero) digits is 756000, while the sum is 44.

The square root of 645565760 is about 25407.9861460919. The cubic root of 645565760 is about 864.2648079481.

The spelling of 645565760 in words is "six hundred forty-five million, five hundred sixty-five thousand, seven hundred sixty".