64640688 has 40 divisors (see below), whose sum is σ = 190844928. Its totient is φ = 18468672.

The previous prime is 64640687. The next prime is 64640713. The reversal of 64640688 is 88604646.

It is a super-2 number, since 2×64640688² = 8356837090226688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (64640683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95856 + ... + 96527.

Almost surely, 2^64640688 is an apocalyptic number.

It is an amenable number.

64640688 is an abundant number, since it is smaller than the sum of its proper divisors (126204240).

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

64640688 is a wasteful number, since it uses less digits than its factorization.

64640688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192401 (or 192395 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 42.

The square root of 64640688 is about 8039.9432833820. The cubic root of 64640688 is about 401.3303372685.

The spelling of 64640688 in words is "sixty-four million, six hundred forty thousand, six hundred eighty-eight".