668655089856 has 224 divisors, whose sum is σ = 2189931307200. Its totient is φ = 198645350400.

The previous prime is 668655089849. The next prime is 668655089873. The reversal of 668655089856 is 658980556866.

668655089856 is a `hidden beast` number, since 6 + 6 + 8 + 65 + 508 + 9 + 8 + 56 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 138256 + ... + 1164656.

It is an arithmetic number, because the mean of its divisors is an integer number (9776479050).

Almost surely, 2^668655089856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668655089856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1094965653600).

668655089856 is an abundant number, since it is smaller than the sum of its proper divisors (1521276217344).

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

668655089856 is a wasteful number, since it uses less digits than its factorization.

668655089856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1026464 (or 1026448 counting only the distinct ones).

The product of its (nonzero) digits is 746496000, while the sum is 72.

The spelling of 668655089856 in words is "six hundred sixty-eight billion, six hundred fifty-five million, eighty-nine thousand, eight hundred fifty-six".