85155991 has 2 divisors, whose sum is σ = 85155992. Its totient is φ = 85155990.

The previous prime is 85155989. The next prime is 85156003. The reversal of 85155991 is 19955158.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 85155991 - 2¹ = 85155989 is a prime.

Together with 85155989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85155901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42577995 + 42577996.

It is an arithmetic number, because the mean of its divisors is an integer number (42577996).

Almost surely, 2^85155991 is an apocalyptic number.

85155991 is a deficient number, since it is larger than the sum of its proper divisors (1).

85155991 is an equidigital number, since it uses as much as digits as its factorization.

85155991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81000, while the sum is 43.

The square root of 85155991 is about 9228.0003792804. Note that the first 3 decimals coincide. The cubic root of 85155991 is about 439.9517698512.

The spelling of 85155991 in words is "eighty-five million, one hundred fifty-five thousand, nine hundred ninety-one".