81179873 has 2 divisors, whose sum is σ = 81179874. Its totient is φ = 81179872.

The previous prime is 81179863. The next prime is 81179881. The reversal of 81179873 is 37897118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81126049 + 53824 = 9007^2 + 232^2 .

It is a cyclic number.

It is not a de Polignac number, because 81179873 - 2⁶ = 81179809 is a prime.

It is a super-2 number, since 2×81179873² = 13180343560592258, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81179803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40589936 + 40589937.

It is an arithmetic number, because the mean of its divisors is an integer number (40589937).

Almost surely, 2^81179873 is an apocalyptic number.

It is an amenable number.

81179873 is a deficient number, since it is larger than the sum of its proper divisors (1).

81179873 is an equidigital number, since it uses as much as digits as its factorization.

81179873 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 44.

The square root of 81179873 is about 9009.9874028769. The cubic root of 81179873 is about 432.9949080858.

The spelling of 81179873 in words is "eighty-one million, one hundred seventy-nine thousand, eight hundred seventy-three".