645915580 has 48 divisors (see below), whose sum is σ = 1382724000. Its totient is φ = 253382400.

The previous prime is 645915563. The next prime is 645915617. The reversal of 645915580 is 85519546.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 608250 + ... + 609310.

It is an arithmetic number, because the mean of its divisors is an integer number (28806750).

Almost surely, 2^645915580 is an apocalyptic number.

It is an amenable number.

645915580 is an abundant number, since it is smaller than the sum of its proper divisors (736808420).

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

645915580 is a wasteful number, since it uses less digits than its factorization.

645915580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1630 (or 1628 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 43.

The square root of 645915580 is about 25414.8692697798. The cubic root of 645915580 is about 864.4208893989.

The spelling of 645915580 in words is "six hundred forty-five million, nine hundred fifteen thousand, five hundred eighty".