81704131 has 2 divisors, whose sum is σ = 81704132. Its totient is φ = 81704130.

The previous prime is 81704113. The next prime is 81704143. The reversal of 81704131 is 13140718.

Together with previous prime (81704113) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81704131 - 2⁵ = 81704099 is a prime.

It is a super-2 number, since 2×81704131² = 13351130044930322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81704096 and 81704105.

It is not a weakly prime, because it can be changed into another prime (81704191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40852065 + 40852066.

It is an arithmetic number, because the mean of its divisors is an integer number (40852066).

Almost surely, 2^81704131 is an apocalyptic number.

81704131 is a deficient number, since it is larger than the sum of its proper divisors (1).

81704131 is an equidigital number, since it uses as much as digits as its factorization.

81704131 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 81704131 is about 9039.0337426077. The cubic root of 81704131 is about 433.9249996046.

Adding to 81704131 its reverse (13140718), we get a palindrome (94844849).

The spelling of 81704131 in words is "eighty-one million, seven hundred four thousand, one hundred thirty-one".