85705231 has 2 divisors, whose sum is σ = 85705232. Its totient is φ = 85705230.

The previous prime is 85705171. The next prime is 85705253. The reversal of 85705231 is 13250758.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 85705231 - 2¹⁹ = 85180943 is a prime.

It is a super-2 number, since 2×85705231² = 14690773241526722, 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 = 85705193 and 85705202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85705031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42852615 + 42852616.

It is an arithmetic number, because the mean of its divisors is an integer number (42852616).

Almost surely, 2^85705231 is an apocalyptic number.

85705231 is a deficient number, since it is larger than the sum of its proper divisors (1).

85705231 is an equidigital number, since it uses as much as digits as its factorization.

85705231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 85705231 is about 9257.7119743487. The cubic root of 85705231 is about 440.8956120557.

Adding to 85705231 its reverse (13250758), we get a palindrome (98955989).

The spelling of 85705231 in words is "eighty-five million, seven hundred five thousand, two hundred thirty-one".