181531964412 has 72 divisors (see below), whose sum is σ = 468834518880. Its totient is φ = 59203347840.

The previous prime is 181531964381. The next prime is 181531964429. The reversal of 181531964412 is 214469135181.

181531964412 is a `hidden beast` number, since 1 + 8 + 15 + 3 + 196 + 441 + 2 = 666.

It is a congruent number.

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, 552462 + ... + 817482.

It is an arithmetic number, because the mean of its divisors is an integer number (6511590540).

Almost surely, 2^181531964412 is an apocalyptic number.

181531964412 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 181531964412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (234417259440).

181531964412 is an abundant number, since it is smaller than the sum of its proper divisors (287302554468).

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

181531964412 is a wasteful number, since it uses less digits than its factorization.

181531964412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265443 (or 265438 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The spelling of 181531964412 in words is "one hundred eighty-one billion, five hundred thirty-one million, nine hundred sixty-four thousand, four hundred twelve".