181561251312 has 240 divisors, whose sum is σ = 585751795200. Its totient is φ = 51425515008.

The previous prime is 181561251301. The next prime is 181561251379. The reversal of 181561251312 is 213152165181.

181561251312 is a `hidden beast` number, since 1 + 8 + 1 + 5 + 612 + 5 + 1 + 31 + 2 = 666.

181561251312 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 111591843 + ... + 111593469.

It is an arithmetic number, because the mean of its divisors is an integer number (2440632480).

Almost surely, 2^181561251312 is an apocalyptic number.

181561251312 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 181561251312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (292875897600).

181561251312 is an abundant number, since it is smaller than the sum of its proper divisors (404190543888).

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

181561251312 is a wasteful number, since it uses less digits than its factorization.

181561251312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2540 (or 2531 counting only the distinct ones).

The product of its digits is 14400, while the sum is 36.

The spelling of 181561251312 in words is "one hundred eighty-one billion, five hundred sixty-one million, two hundred fifty-one thousand, three hundred twelve".