168156781668 has 72 divisors (see below), whose sum is σ = 428925271320. Its totient is φ = 55544401920.

The previous prime is 168156781657. The next prime is 168156781699. The reversal of 168156781668 is 866187651861.

168156781668 is a `hidden beast` number, since 1 + 6 + 8 + 1 + 567 + 8 + 1 + 6 + 68 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 22776242724 + 145380538944 = 150918^2 + 381288^2 .

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, 2776348 + ... + 2836268.

It is an arithmetic number, because the mean of its divisors is an integer number (5957295435).

Almost surely, 2^168156781668 is an apocalyptic number.

168156781668 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

168156781668 is an abundant number, since it is smaller than the sum of its proper divisors (260768489652).

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

168156781668 is a wasteful number, since it uses less digits than its factorization.

168156781668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60637 (or 60632 counting only the distinct ones).

The product of its digits is 23224320, while the sum is 63.

The spelling of 168156781668 in words is "one hundred sixty-eight billion, one hundred fifty-six million, seven hundred eighty-one thousand, six hundred sixty-eight".