85155989 has 2 divisors, whose sum is σ = 85155990. Its totient is φ = 85155988.

The previous prime is 85155979. The next prime is 85155991. The reversal of 85155989 is 98955158.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 84088900 + 1067089 = 9170^2 + 1033^2 .

It is a cyclic number.

It is not a de Polignac number, because 85155989 - 2¹² = 85151893 is a prime.

Together with 85155991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85155949) 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, 42577994 + 42577995.

It is an arithmetic number, because the mean of its divisors is an integer number (42577995).

Almost surely, 2^85155989 is an apocalyptic number.

It is an amenable number.

85155989 is a deficient number, since it is larger than the sum of its proper divisors (1).

85155989 is an equidigital number, since it uses as much as digits as its factorization.

85155989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648000, while the sum is 50.

The square root of 85155989 is about 9228.0002709146. Note that the first 3 decimals coincide. The cubic root of 85155989 is about 439.9517664070.

The spelling of 85155989 in words is "eighty-five million, one hundred fifty-five thousand, nine hundred eighty-nine".