668597578656 has 144 divisors (see below), whose sum is σ = 2091406443840. Its totient is φ = 186368609280.

The previous prime is 668597578639. The next prime is 668597578667. The reversal of 668597578656 is 656875795866.

668597578656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×668597578656² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1540476 + ... + 1926203.

It is an arithmetic number, because the mean of its divisors is an integer number (14523655860).

Almost surely, 2^668597578656 is an apocalyptic number.

It is an amenable number.

668597578656 is an abundant number, since it is smaller than the sum of its proper divisors (1422808865184).

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

668597578656 is a wasteful number, since it uses less digits than its factorization.

668597578656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3466747 (or 3466732 counting only the distinct ones).

The product of its digits is 4572288000, while the sum is 78.

The spelling of 668597578656 in words is "six hundred sixty-eight billion, five hundred ninety-seven million, five hundred seventy-eight thousand, six hundred fifty-six".