81376881 has 16 divisors (see below), whose sum is σ = 111331584. Its totient is φ = 52847744.

The previous prime is 81376877. The next prime is 81376931. The reversal of 81376881 is 18867318.

It is a cyclic number.

It is not a de Polignac number, because 81376881 - 2² = 81376877 is a prime.

It is a super-2 number, since 2×81376881² = 13244393522576322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81376861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31615 + ... + 34091.

It is an arithmetic number, because the mean of its divisors is an integer number (6958224).

Almost surely, 2^81376881 is an apocalyptic number.

It is an amenable number.

81376881 is a deficient number, since it is larger than the sum of its proper divisors (29954703).

81376881 is a wasteful number, since it uses less digits than its factorization.

81376881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2760.

The product of its digits is 64512, while the sum is 42.

The square root of 81376881 is about 9020.9135346704. The cubic root of 81376881 is about 433.3448903558.

The spelling of 81376881 in words is "eighty-one million, three hundred seventy-six thousand, eight hundred eighty-one".