646684812 has 18 divisors (see below), whose sum is σ = 1634675588. Its totient is φ = 215561592.

The previous prime is 646684771. The next prime is 646684847. The reversal of 646684812 is 218486646.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-3 number, since 3×646684812³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8981698 + ... + 8981769.

Almost surely, 2^646684812 is an apocalyptic number.

It is an amenable number.

646684812 is an abundant number, since it is smaller than the sum of its proper divisors (987990776).

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

646684812 is a wasteful number, since it uses less digits than its factorization.

646684812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17963477 (or 17963472 counting only the distinct ones).

The product of its digits is 442368, while the sum is 45.

The square root of 646684812 is about 25429.9982697601. The cubic root of 646684812 is about 864.7639045140.

The spelling of 646684812 in words is "six hundred forty-six million, six hundred eighty-four thousand, eight hundred twelve".