85156021 has 2 divisors, whose sum is σ = 85156022. Its totient is φ = 85156020.

The previous prime is 85156007. The next prime is 85156031. The reversal of 85156021 is 12065158.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83923921 + 1232100 = 9161^2 + 1110^2 .

It is a cyclic number.

It is not a de Polignac number, because 85156021 - 2⁵ = 85155989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85156031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42578010 + 42578011.

It is an arithmetic number, because the mean of its divisors is an integer number (42578011).

Almost surely, 2^85156021 is an apocalyptic number.

It is an amenable number.

85156021 is a deficient number, since it is larger than the sum of its proper divisors (1).

85156021 is an equidigital number, since it uses as much as digits as its factorization.

85156021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 85156021 is about 9228.0020047679. The cubic root of 85156021 is about 439.9518215154.

The spelling of 85156021 in words is "eighty-five million, one hundred fifty-six thousand, twenty-one".