664538688 has 112 divisors (see below), whose sum is σ = 2131283520. Its totient is φ = 201369600.

The previous prime is 664538681. The next prime is 664538689. The reversal of 664538688 is 886835466.

It is a super-2 number, since 2×664538688² = 883223335697522688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (664538681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1528 + ... + 36488.

Almost surely, 2^664538688 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 664538688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1065641760).

664538688 is an abundant number, since it is smaller than the sum of its proper divisors (1466744832).

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

664538688 is a wasteful number, since it uses less digits than its factorization.

664538688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34993 (or 34977 counting only the distinct ones).

The product of its digits is 6635520, while the sum is 54.

The square root of 664538688 is about 25778.6479086860. The cubic root of 664538688 is about 872.6499937254.

The spelling of 664538688 in words is "six hundred sixty-four million, five hundred thirty-eight thousand, six hundred eighty-eight".