85618781 has 2 divisors, whose sum is σ = 85618782. Its totient is φ = 85618780.

The previous prime is 85618747. The next prime is 85618789. The reversal of 85618781 is 18781658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83265625 + 2353156 = 9125^2 + 1534^2 .

It is a cyclic number.

It is not a de Polignac number, because 85618781 - 2⁶ = 85618717 is a prime.

It is a super-2 number, since 2×85618781² = 14661151319851922, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85618789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42809390 + 42809391.

It is an arithmetic number, because the mean of its divisors is an integer number (42809391).

Almost surely, 2^85618781 is an apocalyptic number.

It is an amenable number.

85618781 is a deficient number, since it is larger than the sum of its proper divisors (1).

85618781 is an equidigital number, since it uses as much as digits as its factorization.

85618781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 107520, while the sum is 44.

The square root of 85618781 is about 9253.0417161061. The cubic root of 85618781 is about 440.7473198688.

The spelling of 85618781 in words is "eighty-five million, six hundred eighteen thousand, seven hundred eighty-one".