64931688 has 48 divisors (see below), whose sum is σ = 177617700. Its totient is φ = 21427200.

The previous prime is 64931651. The next prime is 64931689. The reversal of 64931688 is 88613946.

It can be written as a sum of positive squares in 2 ways, for example, as 64931364 + 324 = 8058^2 + 18^2 .

It is a super-2 number, since 2×64931688² = 8432248213058688, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (64931689) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2808 + ... + 11736.

Almost surely, 2^64931688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64931688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88808850).

64931688 is an abundant number, since it is smaller than the sum of its proper divisors (112686012).

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

64931688 is a wasteful number, since it uses less digits than its factorization.

64931688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9042 (or 9035 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 64931688 is about 8058.0201042191. The cubic root of 64931688 is about 401.9316732466.

The spelling of 64931688 in words is "sixty-four million, nine hundred thirty-one thousand, six hundred eighty-eight".