64661688 has 192 divisors, whose sum is σ = 220147200. Its totient is φ = 16692480.

The previous prime is 64661687. The next prime is 64661719. The reversal of 64661688 is 88616646.

It is a super-2 number, since 2×64661688² = 8362267790018688, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64661683) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 465123 + ... + 465261.

It is an arithmetic number, because the mean of its divisors is an integer number (1146600).

Almost surely, 2^64661688 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 64661688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110073600).

64661688 is an abundant number, since it is smaller than the sum of its proper divisors (155485512).

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

64661688 is a wasteful number, since it uses less digits than its factorization.

64661688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242 (or 235 counting only the distinct ones).

The product of its digits is 331776, while the sum is 45.

The square root of 64661688 is about 8041.2491566920. The cubic root of 64661688 is about 401.3737929971.

The spelling of 64661688 in words is "sixty-four million, six hundred sixty-one thousand, six hundred eighty-eight".