181399585920 has 256 divisors, whose sum is σ = 661641523200. Its totient is φ = 41410768896.

The previous prime is 181399585901. The next prime is 181399585949. The reversal of 181399585920 is 29585993181.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11268117 + ... + 11284203.

It is an arithmetic number, because the mean of its divisors is an integer number (2584537200).

Almost surely, 2^181399585920 is an apocalyptic number.

181399585920 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 181399585920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (330820761600).

181399585920 is an abundant number, since it is smaller than the sum of its proper divisors (480241937280).

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

181399585920 is a wasteful number, since it uses less digits than its factorization.

181399585920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16955 (or 16943 counting only the distinct ones).

The product of its (nonzero) digits is 6998400, while the sum is 60.

The spelling of 181399585920 in words is "one hundred eighty-one billion, three hundred ninety-nine million, five hundred eighty-five thousand, nine hundred twenty".