85009009 has 2 divisors, whose sum is σ = 85009010. Its totient is φ = 85009008.

The previous prime is 85009007. The next prime is 85009033. The reversal of 85009009 is 90090058.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52519009 + 32490000 = 7247^2 + 5700^2 .

It is a cyclic number.

It is not a de Polignac number, because 85009009 - 2¹ = 85009007 is a prime.

It is a super-4 number, since 4×85009009⁴ (a number of 33 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

Together with 85009007, it forms a pair of twin primes.

85009009 is a modest number, since divided by 9009 gives 85 as remainder.

It is not a weakly prime, because it can be changed into another prime (85009007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42504504 + 42504505.

It is an arithmetic number, because the mean of its divisors is an integer number (42504505).

Almost surely, 2^85009009 is an apocalyptic number.

It is an amenable number.

85009009 is a deficient number, since it is larger than the sum of its proper divisors (1).

85009009 is an equidigital number, since it uses as much as digits as its factorization.

85009009 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 85009009 is about 9220.0330259712. The cubic root of 85009009 is about 439.6985004076.

It can be divided in two parts, 8500 and 9009, that multiplied together give a triangular number (76576500 = T₁₂₃₇₅).

The spelling of 85009009 in words is "eighty-five million, nine thousand, nine".