181815972 has 48 divisors (see below), whose sum is σ = 462685440. Its totient is φ = 55231488.

The previous prime is 181815971. The next prime is 181815979. The reversal of 181815972 is 279518181.

It is not an unprimeable number, because it can be changed into a prime (181815971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4948 + ... + 19700.

It is an arithmetic number, because the mean of its divisors is an integer number (9639280).

Almost surely, 2^181815972 is an apocalyptic number.

181815972 is a gapful number since it is divisible by the number (12) 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 181815972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (231342720).

181815972 is an abundant number, since it is smaller than the sum of its proper divisors (280869468).

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

181815972 is a wasteful number, since it uses less digits than its factorization.

181815972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14852 (or 14850 counting only the distinct ones).

The product of its digits is 40320, while the sum is 42.

The square root of 181815972 is about 13483.9153067646. The cubic root of 181815972 is about 566.5140397869.

The spelling of 181815972 in words is "one hundred eighty-one million, eight hundred fifteen thousand, nine hundred seventy-two".