665931881502720 has 5760 divisors, whose sum is σ = 3060028075104000. Its totient is φ = 137557833154560.

The previous prime is 665931881502707. The next prime is 665931881502731. The reversal of 665931881502720 is 27205188139566.

665931881502720 is a `hidden beast` number, since 6 + 6 + 5 + 93 + 18 + 8 + 1 + 502 + 7 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (5760).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 2933620623247 + ... + 2933620623473.

It is an arithmetic number, because the mean of its divisors is an integer number (531254874150).

Almost surely, 2^{665931881502720} is an apocalyptic number.

665931881502720 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 665931881502720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1530014037552000).

665931881502720 is an abundant number, since it is smaller than the sum of its proper divisors (2394096193601280).

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

665931881502720 is a wasteful number, since it uses less digits than its factorization.

665931881502720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459 (or 423 counting only the distinct ones).

The product of its (nonzero) digits is 43545600, while the sum is 63.

The spelling of 665931881502720 in words is "six hundred sixty-five trillion, nine hundred thirty-one billion, eight hundred eighty-one million, five hundred two thousand, seven hundred twenty".