646721577604260 has 120 divisors (see below), whose sum is σ = 2028816310192056. Its totient is φ = 172456811873280.

The previous prime is 646721577604241. The next prime is 646721577604409. The reversal of 646721577604260 is 62406775127646.

646721577604260 is a `hidden beast` number, since 6 + 4 + 6 + 7 + 2 + 15 + 7 + 7 + 604 + 2 + 6 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 55692577860516 + 591028999743744 = 7462746^2 + 24311088^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 122003850 + ... + 127194270.

Almost surely, 2^{646721577604260} is an apocalyptic number.

646721577604260 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

646721577604260 is an abundant number, since it is smaller than the sum of its proper divisors (1382094732587796).

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

646721577604260 is a wasteful number, since it uses less digits than its factorization.

646721577604260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5267355 (or 5267344 counting only the distinct ones).

The product of its (nonzero) digits is 142248960, while the sum is 63.

The spelling of 646721577604260 in words is "six hundred forty-six trillion, seven hundred twenty-one billion, five hundred seventy-seven million, six hundred four thousand, two hundred sixty".