81686160 has 60 divisors (see below), whose sum is σ = 274331772. Its totient is φ = 21782784.

The previous prime is 81686153. The next prime is 81686161. The reversal of 81686160 is 6168618.

It can be written as a sum of positive squares in 2 ways, for example, as 27751824 + 53934336 = 5268^2 + 7344^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (81686161) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 56007 + ... + 57446.

Almost surely, 2^81686160 is an apocalyptic number.

81686160 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81686160 is an abundant number, since it is smaller than the sum of its proper divisors (192645612).

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

81686160 is a wasteful number, since it uses less digits than its factorization.

81686160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113472 (or 113463 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 81686160 is about 9038.0396104465. The cubic root of 81686160 is about 433.8931830250.

The spelling of 81686160 in words is "eighty-one million, six hundred eighty-six thousand, one hundred sixty".