85972181 has 2 divisors, whose sum is σ = 85972182. Its totient is φ = 85972180.

The previous prime is 85972157. The next prime is 85972193. The reversal of 85972181 is 18127958.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63457156 + 22515025 = 7966^2 + 4745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85972181 is a prime.

It is a super-2 number, since 2×85972181² = 14782431811793522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85972141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42986090 + 42986091.

It is an arithmetic number, because the mean of its divisors is an integer number (42986091).

Almost surely, 2^85972181 is an apocalyptic number.

It is an amenable number.

85972181 is a deficient number, since it is larger than the sum of its proper divisors (1).

85972181 is an equidigital number, since it uses as much as digits as its factorization.

85972181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 41.

The square root of 85972181 is about 9272.1184742215. The cubic root of 85972181 is about 441.3528968463.

The spelling of 85972181 in words is "eighty-five million, nine hundred seventy-two thousand, one hundred eighty-one".