81238117 has 2 divisors, whose sum is σ = 81238118. Its totient is φ = 81238116.

The previous prime is 81238111. The next prime is 81238127. The reversal of 81238117 is 71183218.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41912676 + 39325441 = 6474^2 + 6271^2 .

It is a cyclic number.

It is not a de Polignac number, because 81238117 - 2³ = 81238109 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81238111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40619058 + 40619059.

It is an arithmetic number, because the mean of its divisors is an integer number (40619059).

Almost surely, 2^81238117 is an apocalyptic number.

It is an amenable number.

81238117 is a deficient number, since it is larger than the sum of its proper divisors (1).

81238117 is an equidigital number, since it uses as much as digits as its factorization.

81238117 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 31.

The square root of 81238117 is about 9013.2190143145. The cubic root of 81238117 is about 433.0984367296.

The spelling of 81238117 in words is "eighty-one million, two hundred thirty-eight thousand, one hundred seventeen".