81168857 has 24 divisors (see below), whose sum is σ = 103701696. Its totient is φ = 62172000.

The previous prime is 81168853. The next prime is 81168869. The reversal of 81168857 is 75886118.

It is not a de Polignac number, because 81168857 - 2² = 81168853 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81168853) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 50882 + ... + 52452.

It is an arithmetic number, because the mean of its divisors is an integer number (4320904).

Almost surely, 2^81168857 is an apocalyptic number.

It is an amenable number.

81168857 is a deficient number, since it is larger than the sum of its proper divisors (22532839).

81168857 is a wasteful number, since it uses less digits than its factorization.

81168857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1661 (or 1650 counting only the distinct ones).

The product of its digits is 107520, while the sum is 44.

The square root of 81168857 is about 9009.3760605272. The cubic root of 81168857 is about 432.9753215902.

The spelling of 81168857 in words is "eighty-one million, one hundred sixty-eight thousand, eight hundred fifty-seven".