85000009 has 2 divisors, whose sum is σ = 85000010. Its totient is φ = 85000008.

The previous prime is 85000007. The next prime is 85000021. The reversal of 85000009 is 90000058.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 84272400 + 727609 = 9180^2 + 853^2 .

It is a cyclic number.

It is not a de Polignac number, because 85000009 - 2¹ = 85000007 is a prime.

Together with 85000007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (85000007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42500004 + 42500005.

It is an arithmetic number, because the mean of its divisors is an integer number (42500005).

Almost surely, 2^85000009 is an apocalyptic number.

It is an amenable number.

85000009 is a deficient number, since it is larger than the sum of its proper divisors (1).

85000009 is an equidigital number, since it uses as much as digits as its factorization.

85000009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 85000009 is about 9219.5449453864. The cubic root of 85000009 is about 439.6829827340.

The spelling of 85000009 in words is "eighty-five million, nine", and thus it is an aban number and an uban number.