664210656 has 72 divisors (see below), whose sum is σ = 1900571400. Its totient is φ = 220029696.

The previous prime is 664210579. The next prime is 664210663. The reversal of 664210656 is 656012466.

It is a happy number.

664210656 is a `hidden beast` number, since 6 + 642 + 1 + 0 + 6 + 5 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 664210656.

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, 39870 + ... + 54018.

It is an arithmetic number, because the mean of its divisors is an integer number (26396825).

Almost surely, 2^664210656 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 664210656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (950285700).

664210656 is an abundant number, since it is smaller than the sum of its proper divisors (1236360744).

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

664210656 is a wasteful number, since it uses less digits than its factorization.

664210656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14328 (or 14317 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 664210656 is about 25772.2846484358. The cubic root of 664210656 is about 872.5063832069.

The spelling of 664210656 in words is "six hundred sixty-four million, two hundred ten thousand, six hundred fifty-six".