81155412 has 48 divisors (see below), whose sum is σ = 226591680. Its totient is φ = 24970464.

The previous prime is 81155411. The next prime is 81155423. The reversal of 81155412 is 21455118.

81155412 is a `hidden beast` number, since 8 + 115 + 541 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81155411) 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, 27498 + ... + 30305.

It is an arithmetic number, because the mean of its divisors is an integer number (4720660).

Almost surely, 2^81155412 is an apocalyptic number.

It is an amenable number.

81155412 is an abundant number, since it is smaller than the sum of its proper divisors (145436268).

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

81155412 is a wasteful number, since it uses less digits than its factorization.

81155412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57829 (or 57821 counting only the distinct ones).

The product of its digits is 1600, while the sum is 27.

The square root of 81155412 is about 9008.6298625263. The cubic root of 81155412 is about 432.9514139206.

The spelling of 81155412 in words is "eighty-one million, one hundred fifty-five thousand, four hundred twelve".