81168681 has 8 divisors (see below), whose sum is σ = 118063584. Its totient is φ = 49193120.

The previous prime is 81168673. The next prime is 81168707. The reversal of 81168681 is 18686118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81168681 - 2³ = 81168673 is a prime.

It is a super-2 number, since 2×81168681² = 13176709550559522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81168611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1229796 + ... + 1229861.

It is an arithmetic number, because the mean of its divisors is an integer number (14757948).

Almost surely, 2^81168681 is an apocalyptic number.

It is an amenable number.

81168681 is a deficient number, since it is larger than the sum of its proper divisors (36894903).

81168681 is a wasteful number, since it uses less digits than its factorization.

81168681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2459671.

The product of its digits is 18432, while the sum is 39.

The square root of 81168681 is about 9009.3662929198. The cubic root of 81168681 is about 432.9750086471.

The spelling of 81168681 in words is "eighty-one million, one hundred sixty-eight thousand, six hundred eighty-one".