645543512660 has 12 divisors (see below), whose sum is σ = 1355641376628. Its totient is φ = 258217405056.

The previous prime is 645543512659. The next prime is 645543512693. The reversal of 645543512660 is 66215345546.

It can be written as a sum of positive squares in 2 ways, for example, as 213292490896 + 432251021764 = 461836^2 + 657458^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16138587797 + ... + 16138587836.

It is an arithmetic number, because the mean of its divisors is an integer number (112970114719).

Almost surely, 2^645543512660 is an apocalyptic number.

It is an amenable number.

645543512660 is an abundant number, since it is smaller than the sum of its proper divisors (710097863968).

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

645543512660 is a wasteful number, since it uses less digits than its factorization.

645543512660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32277175642 (or 32277175640 counting only the distinct ones).

The product of its (nonzero) digits is 2592000, while the sum is 47.

The spelling of 645543512660 in words is "six hundred forty-five billion, five hundred forty-three million, five hundred twelve thousand, six hundred sixty".