64641664 has 32 divisors (see below), whose sum is σ = 132268500. Its totient is φ = 31444992.

The previous prime is 64641659. The next prime is 64641677. The reversal of 64641664 is 46614646.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 64641600 + 64 = 8040^2 + 8^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (37).

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, 2089 + ... + 11560.

Almost surely, 2^64641664 is an apocalyptic number.

64641664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

64641664 is an abundant number, since it is smaller than the sum of its proper divisors (67626836).

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

64641664 is a wasteful number, since it uses less digits than its factorization.

64641664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13700 (or 13688 counting only the distinct ones).

The product of its digits is 82944, while the sum is 37.

The square root of 64641664 is about 8040.0039800985. The cubic root of 64641664 is about 401.3323571337.

It can be divided in two parts, 646416 and 64, that multiplied together give a square (41370624 = 6432²).

The spelling of 64641664 in words is "sixty-four million, six hundred forty-one thousand, six hundred sixty-four".