85640081 has 2 divisors, whose sum is σ = 85640082. Its totient is φ = 85640080.

The previous prime is 85640069. The next prime is 85640099. The reversal of 85640081 is 18004658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75342400 + 10297681 = 8680^2 + 3209^2 .

It is a cyclic number.

It is not a de Polignac number, because 85640081 - 2¹⁴ = 85623697 is a prime.

It is a super-2 number, since 2×85640081² = 14668446947373122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (85640281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42820040 + 42820041.

It is an arithmetic number, because the mean of its divisors is an integer number (42820041).

Almost surely, 2^85640081 is an apocalyptic number.

It is an amenable number.

85640081 is a deficient number, since it is larger than the sum of its proper divisors (1).

85640081 is an equidigital number, since it uses as much as digits as its factorization.

85640081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 85640081 is about 9254.1926174032. The cubic root of 85640081 is about 440.7838661320.

The spelling of 85640081 in words is "eighty-five million, six hundred forty thousand, eighty-one".