664399216800 has 576 divisors, whose sum is σ = 2705946808320. Its totient is φ = 155869056000.

The previous prime is 664399216781. The next prime is 664399216813. The reversal of 664399216800 is 8612993466.

664399216800 is a `hidden beast` number, since 66 + 439 + 92 + 1 + 68 + 0 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7320499 + ... + 7410701.

It is an arithmetic number, because the mean of its divisors is an integer number (4697824320).

Almost surely, 2^664399216800 is an apocalyptic number.

664399216800 is a gapful number since it is divisible by the number (60) 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 664399216800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1352973404160).

664399216800 is an abundant number, since it is smaller than the sum of its proper divisors (2041547591520).

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

664399216800 is a wasteful number, since it uses less digits than its factorization.

664399216800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90274 (or 90255 counting only the distinct ones).

The product of its (nonzero) digits is 3359232, while the sum is 54.

The spelling of 664399216800 in words is "six hundred sixty-four billion, three hundred ninety-nine million, two hundred sixteen thousand, eight hundred".