668239427856 has 480 divisors, whose sum is σ = 2435340128256. Its totient is φ = 155046528000.

The previous prime is 668239427827. The next prime is 668239427861. The reversal of 668239427856 is 658724932866.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10394371 + ... + 10458461.

Almost surely, 2^668239427856 is an apocalyptic number.

668239427856 is a gapful number since it is divisible by the number (66) 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 668239427856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1217670064128).

668239427856 is an abundant number, since it is smaller than the sum of its proper divisors (1767100700400).

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

668239427856 is a wasteful number, since it uses less digits than its factorization.

668239427856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64171 (or 64158 counting only the distinct ones).

The product of its digits is 209018880, while the sum is 66.

The spelling of 668239427856 in words is "six hundred sixty-eight billion, two hundred thirty-nine million, four hundred twenty-seven thousand, eight hundred fifty-six".