81164160 has 512 divisors, whose sum is σ = 364262400. Its totient is φ = 16588800.

The previous prime is 81164141. The next prime is 81164189. The reversal of 81164160 is 6146118.

81164160 is a `hidden beast` number, since 8 + 11 + 641 + 6 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 1330530 + ... + 1330590.

It is an arithmetic number, because the mean of its divisors is an integer number (711450).

Almost surely, 2^81164160 is an apocalyptic number.

81164160 is a gapful number since it is divisible by the number (80) 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 81164160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (182131200).

81164160 is an abundant number, since it is smaller than the sum of its proper divisors (283098240).

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

81164160 is a wasteful number, since it uses less digits than its factorization.

81164160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 81164160 is about 9009.1153838765. The cubic root of 81164160 is about 432.9669697650.

The spelling of 81164160 in words is "eighty-one million, one hundred sixty-four thousand, one hundred sixty".