181691332864 has 72 divisors (see below), whose sum is σ = 383626357632. Its totient is φ = 85705297920.

The previous prime is 181691332861. The next prime is 181691332883. The reversal of 181691332864 is 468233196181.

It is not an unprimeable number, because it can be changed into a prime (181691332861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 218469 + ... + 641179.

It is an arithmetic number, because the mean of its divisors is an integer number (5328143856).

Almost surely, 2^181691332864 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 181691332864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191813178816).

181691332864 is an abundant number, since it is smaller than the sum of its proper divisors (201935024768).

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

181691332864 is an equidigital number, since it uses as much as digits as its factorization.

181691332864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422823 (or 422809 counting only the distinct ones).

The product of its digits is 1492992, while the sum is 52.

The spelling of 181691332864 in words is "one hundred eighty-one billion, six hundred ninety-one million, three hundred thirty-two thousand, eight hundred sixty-four".