668568637440 has 936 divisors, whose sum is σ = 2632137091584. Its totient is φ = 156686745600.

The previous prime is 668568637433. The next prime is 668568637483. The reversal of 668568637440 is 44736865866.

668568637440 is a `hidden beast` number, since 6 + 6 + 8 + 568 + 63 + 7 + 4 + 4 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 691383837 + ... + 691384803.

Almost surely, 2^668568637440 is an apocalyptic number.

668568637440 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 668568637440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1316068545792).

668568637440 is an abundant number, since it is smaller than the sum of its proper divisors (1963568454144).

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

668568637440 is a wasteful number, since it uses less digits than its factorization.

668568637440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1055 (or 1019 counting only the distinct ones).

The product of its (nonzero) digits is 139345920, while the sum is 63.

The spelling of 668568637440 in words is "six hundred sixty-eight billion, five hundred sixty-eight million, six hundred thirty-seven thousand, four hundred forty".