64643664 has 20 divisors (see below), whose sum is σ = 166996256. Its totient is φ = 21547872.

The previous prime is 64643647. The next prime is 64643687. The reversal of 64643664 is 46634646.

64643664 is nontrivially palindromic in base 14.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

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, 673324 + ... + 673419.

Almost surely, 2^64643664 is an apocalyptic number.

It is an amenable number.

64643664 is an abundant number, since it is smaller than the sum of its proper divisors (102352592).

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

64643664 is a wasteful number, since it uses less digits than its factorization.

64643664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1346754 (or 1346748 counting only the distinct ones).

The product of its digits is 248832, while the sum is 39.

The square root of 64643664 is about 8040.1283571844. The cubic root of 64643664 is about 401.3364961383.

The spelling of 64643664 in words is "sixty-four million, six hundred forty-three thousand, six hundred sixty-four".