85847981 has 2 divisors, whose sum is σ = 85847982. Its totient is φ = 85847980.

The previous prime is 85847941. The next prime is 85847987. The reversal of 85847981 is 18974858.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83429956 + 2418025 = 9134^2 + 1555^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85847981 is a prime.

It is a super-2 number, since 2×85847981² = 14739751683552722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85847987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42923990 + 42923991.

It is an arithmetic number, because the mean of its divisors is an integer number (42923991).

Almost surely, 2^85847981 is an apocalyptic number.

It is an amenable number.

85847981 is a deficient number, since it is larger than the sum of its proper divisors (1).

85847981 is an equidigital number, since it uses as much as digits as its factorization.

85847981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 645120, while the sum is 50.

The square root of 85847981 is about 9265.4185550357. The cubic root of 85847981 is about 441.1402604365.

The spelling of 85847981 in words is "eighty-five million, eight hundred forty-seven thousand, nine hundred eighty-one".