156991796881920 has 8640 divisors, whose sum is σ = 818214876610560. Its totient is φ = 27389834035200.

The previous prime is 156991796881783. The next prime is 156991796881921. The reversal of 156991796881920 is 29188697199651.

156991796881920 is a `hidden beast` number, since 1 + 569 + 9 + 17 + 9 + 6 + 8 + 8 + 19 + 20 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 156991796881920.

It is not an unprimeable number, because it can be changed into a prime (156991796881921) by changing a digit.

It is a polite number, since it can be written in 863 ways as a sum of consecutive naturals, for example, 1236155880897 + ... + 1236155881023.

It is an arithmetic number, because the mean of its divisors is an integer number (94700795904).

Almost surely, 2^{156991796881920} is an apocalyptic number.

156991796881920 is a gapful number since it is divisible by the number (10) 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 156991796881920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (409107438305280).

156991796881920 is an abundant number, since it is smaller than the sum of its proper divisors (661223079728640).

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

156991796881920 is a wasteful number, since it uses less digits than its factorization.

156991796881920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 1058158080, while the sum is 81.

The spelling of 156991796881920 in words is "one hundred fifty-six trillion, nine hundred ninety-one billion, seven hundred ninety-six million, eight hundred eighty-one thousand, nine hundred twenty".