85931009 has 2 divisors, whose sum is σ = 85931010. Its totient is φ = 85931008.

The previous prime is 85930981. The next prime is 85931023. The reversal of 85931009 is 90013958.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58599025 + 27331984 = 7655^2 + 5228^2 .

It is a cyclic number.

It is not a de Polignac number, because 85931009 - 2⁸ = 85930753 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 85931009.

It is not a weakly prime, because it can be changed into another prime (85931609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42965504 + 42965505.

It is an arithmetic number, because the mean of its divisors is an integer number (42965505).

Almost surely, 2^85931009 is an apocalyptic number.

It is an amenable number.

85931009 is a deficient number, since it is larger than the sum of its proper divisors (1).

85931009 is an equidigital number, since it uses as much as digits as its factorization.

85931009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 85931009 is about 9269.8980037539. The cubic root of 85931009 is about 441.2824310949.

The spelling of 85931009 in words is "eighty-five million, nine hundred thirty-one thousand, nine".