81856180 has 48 divisors (see below), whose sum is σ = 206801280. Its totient is φ = 26587008.

The previous prime is 81856169. The next prime is 81856223. The reversal of 81856180 is 8165818.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12727 + ... + 18046.

It is an arithmetic number, because the mean of its divisors is an integer number (4308360).

Almost surely, 2^81856180 is an apocalyptic number.

It is an amenable number.

81856180 is an abundant number, since it is smaller than the sum of its proper divisors (124945100).

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

81856180 is a wasteful number, since it uses less digits than its factorization.

81856180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30808 (or 30806 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 37.

The square root of 81856180 is about 9047.4405220482. The cubic root of 81856180 is about 434.1940067164.

It can be divided in two parts, 8185 and 6180, that added together give a triangular number (14365 = T₁₆₉).

The spelling of 81856180 in words is "eighty-one million, eight hundred fifty-six thousand, one hundred eighty".