85817131 has 2 divisors, whose sum is σ = 85817132. Its totient is φ = 85817130.

The previous prime is 85817113. The next prime is 85817191. The reversal of 85817131 is 13171858.

Together with previous prime (85817113) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85817131 is a prime.

It is a super-2 number, since 2×85817131² = 14729159946142322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (85817191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42908565 + 42908566.

It is an arithmetic number, because the mean of its divisors is an integer number (42908566).

Almost surely, 2^85817131 is an apocalyptic number.

85817131 is a deficient number, since it is larger than the sum of its proper divisors (1).

85817131 is an equidigital number, since it uses as much as digits as its factorization.

85817131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6720, while the sum is 34.

The square root of 85817131 is about 9263.7536128721. The cubic root of 85817131 is about 441.0874119502.

Adding to 85817131 its reverse (13171858), we get a palindrome (98988989).

It can be divided in two parts, 85 and 817131, that added together give a square (817216 = 904²).

The spelling of 85817131 in words is "eighty-five million, eight hundred seventeen thousand, one hundred thirty-one".