646912564 has 12 divisors (see below), whose sum is σ = 1150656388. Its totient is φ = 318153600.

The previous prime is 646912561. The next prime is 646912579. The reversal of 646912564 is 465219646.

It can be written as a sum of positive squares in 2 ways, for example, as 13987600 + 632924964 = 3740^2 + 25158^2 .

It is a super-2 number, since 2×646912564² = 836991730922108192, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 646912564.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646912561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1325397 + ... + 1325884.

Almost surely, 2^646912564 is an apocalyptic number.

It is an amenable number.

646912564 is a deficient number, since it is larger than the sum of its proper divisors (503743824).

646912564 is a wasteful number, since it uses less digits than its factorization.

646912564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2651346 (or 2651344 counting only the distinct ones).

The product of its digits is 311040, while the sum is 43.

The square root of 646912564 is about 25434.4758939515. The cubic root of 646912564 is about 864.8654112494.

The spelling of 646912564 in words is "six hundred forty-six million, nine hundred twelve thousand, five hundred sixty-four".