646919664 has 20 divisors (see below), whose sum is σ = 1671209256. Its totient is φ = 215639872.

The previous prime is 646919653. The next prime is 646919671. The reversal of 646919664 is 466919646.

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, 6738699 + ... + 6738794.

Almost surely, 2^646919664 is an apocalyptic number.

It is an amenable number.

646919664 is an abundant number, since it is smaller than the sum of its proper divisors (1024289592).

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

646919664 is a wasteful number, since it uses less digits than its factorization.

646919664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13477504 (or 13477498 counting only the distinct ones).

The product of its digits is 1679616, while the sum is 51.

The square root of 646919664 is about 25434.6154679012. The cubic root of 646919664 is about 864.8685752638.

The spelling of 646919664 in words is "six hundred forty-six million, nine hundred nineteen thousand, six hundred sixty-four".