85172831 has 2 divisors, whose sum is σ = 85172832. Its totient is φ = 85172830.

The previous prime is 85172819. The next prime is 85172837. The reversal of 85172831 is 13827158.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 85172831 - 2⁶ = 85172767 is a prime.

It is a super-2 number, since 2×85172831² = 14508822281109122, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 85172791 and 85172800.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85172837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42586415 + 42586416.

It is an arithmetic number, because the mean of its divisors is an integer number (42586416).

Almost surely, 2^85172831 is an apocalyptic number.

85172831 is a deficient number, since it is larger than the sum of its proper divisors (1).

85172831 is an equidigital number, since it uses as much as digits as its factorization.

85172831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 35.

The square root of 85172831 is about 9228.9127745363. The cubic root of 85172831 is about 439.9807687876.

Adding to 85172831 its reverse (13827158), we get a palindrome (98999989).

The spelling of 85172831 in words is "eighty-five million, one hundred seventy-two thousand, eight hundred thirty-one".