663681392640 has 1680 divisors, whose sum is σ = 2951058518496. Its totient is φ = 139292835840.

The previous prime is 663681392593. The next prime is 663681392653. The reversal of 663681392640 is 46293186366.

663681392640 is a `hidden beast` number, since 6 + 6 + 368 + 13 + 9 + 264 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1680).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 16187351020 + ... + 16187351060.

Almost surely, 2^663681392640 is an apocalyptic number.

663681392640 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 663681392640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1475529259248).

663681392640 is an abundant number, since it is smaller than the sum of its proper divisors (2287377125856).

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

663681392640 is an equidigital number, since it uses as much as digits as its factorization.

663681392640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 75 counting only the distinct ones).

The product of its (nonzero) digits is 6718464, while the sum is 54.

The spelling of 663681392640 in words is "six hundred sixty-three billion, six hundred eighty-one million, three hundred ninety-two thousand, six hundred forty".