81180156 has 24 divisors (see below), whose sum is σ = 197656704. Its totient is φ = 25883440.

The previous prime is 81180149. The next prime is 81180181. The reversal of 81180156 is 65108118.

It is a happy number.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 146790 + ... + 147341.

It is an arithmetic number, because the mean of its divisors is an integer number (8235696).

Almost surely, 2^81180156 is an apocalyptic number.

It is an amenable number.

81180156 is an abundant number, since it is smaller than the sum of its proper divisors (116476548).

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

81180156 is a wasteful number, since it uses less digits than its factorization.

81180156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294161 (or 294159 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 30.

The square root of 81180156 is about 9010.0031076576. The cubic root of 81180156 is about 432.9954112377.

The spelling of 81180156 in words is "eighty-one million, one hundred eighty thousand, one hundred fifty-six".