664905568320 has 560 divisors, whose sum is σ = 2790289210368. Its totient is φ = 147074641920.

The previous prime is 664905568307. The next prime is 664905568367. The reversal of 664905568320 is 23865509466.

664905568320 is a `hidden beast` number, since 6 + 6 + 4 + 9 + 0 + 556 + 83 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (560).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 5565534 + ... + 5683746.

Almost surely, 2^664905568320 is an apocalyptic number.

664905568320 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 664905568320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1395144605184).

664905568320 is an abundant number, since it is smaller than the sum of its proper divisors (2125383642048).

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

664905568320 is a wasteful number, since it uses less digits than its factorization.

664905568320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118280 (or 118261 counting only the distinct ones).

The product of its (nonzero) digits is 9331200, while the sum is 54.

The spelling of 664905568320 in words is "six hundred sixty-four billion, nine hundred five million, five hundred sixty-eight thousand, three hundred twenty".