664521984 has 108 divisors (see below), whose sum is σ = 2189745376. Its totient is φ = 189858816.

The previous prime is 664521929. The next prime is 664522021. The reversal of 664521984 is 489125466.

664521984 is a `hidden beast` number, since 6 + 6 + 452 + 198 + 4 = 666.

It is a super-3 number, since 3×664521984³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4474 + ... + 36729.

Almost surely, 2^664521984 is an apocalyptic number.

664521984 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664521984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1094872688).

664521984 is an abundant number, since it is smaller than the sum of its proper divisors (1525223392).

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

664521984 is a wasteful number, since it uses less digits than its factorization.

664521984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41232 (or 41215 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 664521984 is about 25778.3239175863. The cubic root of 664521984 is about 872.6426819527.

The spelling of 664521984 in words is "six hundred sixty-four million, five hundred twenty-one thousand, nine hundred eighty-four".