85909 has 2 divisors, whose sum is σ = 85910. Its totient is φ = 85908.

The previous prime is 85903. The next prime is 85931. The reversal of 85909 is 90958.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62500 + 23409 = 250^2 + 153^2 .

It is a cyclic number.

It is not a de Polignac number, because 85909 - 2⁷ = 85781 is a prime.

It is a plaindrome in base 14.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42954 + 42955.

It is an arithmetic number, because the mean of its divisors is an integer number (42955).

2⁸⁵⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

85909 is a deficient number, since it is larger than the sum of its proper divisors (1).

85909 is an equidigital number, since it uses as much as digits as its factorization.

85909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 85909 is about 293.1023711948. The cubic root of 85909 is about 44.1244753527.

The spelling of 85909 in words is "eighty-five thousand, nine hundred nine".