81976161 has 4 divisors (see below), whose sum is σ = 109301552. Its totient is φ = 54650772.

The previous prime is 81976129. The next prime is 81976187. The reversal of 81976161 is 16167918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81976161 - 2⁵ = 81976129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81976861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13662691 + ... + 13662696.

It is an arithmetic number, because the mean of its divisors is an integer number (27325388).

Almost surely, 2^81976161 is an apocalyptic number.

It is an amenable number.

81976161 is a deficient number, since it is larger than the sum of its proper divisors (27325391).

81976161 is a wasteful number, since it uses less digits than its factorization.

81976161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27325390.

The product of its digits is 18144, while the sum is 39.

The square root of 81976161 is about 9054.0687538808. The cubic root of 81976161 is about 434.4060436451.

The spelling of 81976161 in words is "eighty-one million, nine hundred seventy-six thousand, one hundred sixty-one".