668591763840 has 1024 divisors, whose sum is σ = 3179399731200. Its totient is φ = 128238059520.

The previous prime is 668591763823. The next prime is 668591763863. The reversal of 668591763840 is 48367195866.

668591763840 is a `hidden beast` number, since 6 + 6 + 8 + 591 + 7 + 6 + 38 + 4 + 0 = 666.

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 polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 17277954 + ... + 17316606.

It is an arithmetic number, because the mean of its divisors is an integer number (3104882550).

Almost surely, 2^668591763840 is an apocalyptic number.

668591763840 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 668591763840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1589699865600).

668591763840 is an abundant number, since it is smaller than the sum of its proper divisors (2510807967360).

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

668591763840 is a wasteful number, since it uses less digits than its factorization.

668591763840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38712 (or 38694 counting only the distinct ones).

The product of its (nonzero) digits is 52254720, while the sum is 63.

The spelling of 668591763840 in words is "six hundred sixty-eight billion, five hundred ninety-one million, seven hundred sixty-three thousand, eight hundred forty".