646612816 has 20 divisors (see below), whose sum is σ = 1326507732. Its totient is φ = 304288256.

The previous prime is 646612783. The next prime is 646612831. The reversal of 646612816 is 618216646.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 581002816 + 65610000 = 24104^2 + 8100^2 .

It is a super-3 number, since 3×646612816³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1188355 + ... + 1188898.

Almost surely, 2^646612816 is an apocalyptic number.

It is an amenable number.

646612816 is an abundant number, since it is smaller than the sum of its proper divisors (679894916).

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

646612816 is a wasteful number, since it uses less digits than its factorization.

646612816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2377278 (or 2377272 counting only the distinct ones).

The product of its digits is 82944, while the sum is 40.

The square root of 646612816 is about 25428.5826581035. The cubic root of 646612816 is about 864.7318116761.

The spelling of 646612816 in words is "six hundred forty-six million, six hundred twelve thousand, eight hundred sixteen".