85679981 has 2 divisors, whose sum is σ = 85679982. Its totient is φ = 85679980.

The previous prime is 85679963. The next prime is 85680011. The reversal of 85679981 is 18997658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 83814025 + 1865956 = 9155^2 + 1366^2 .

It is a cyclic number.

It is not a de Polignac number, because 85679981 - 2²⁶ = 18571117 is a prime.

It is a super-2 number, since 2×85679981² = 14682118288320722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85679921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42839990 + 42839991.

It is an arithmetic number, because the mean of its divisors is an integer number (42839991).

Almost surely, 2^85679981 is an apocalyptic number.

It is an amenable number.

85679981 is a deficient number, since it is larger than the sum of its proper divisors (1).

85679981 is an equidigital number, since it uses as much as digits as its factorization.

85679981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 53.

The square root of 85679981 is about 9256.3481460023. The cubic root of 85679981 is about 440.8523097293.

The spelling of 85679981 in words is "eighty-five million, six hundred seventy-nine thousand, nine hundred eighty-one".