817312681 has 2 divisors, whose sum is σ = 817312682. Its totient is φ = 817312680.

The previous prime is 817312669. The next prime is 817312687. The reversal of 817312681 is 186213718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 655616025 + 161696656 = 25605^2 + 12716^2 .

It is a cyclic number.

It is not a de Polignac number, because 817312681 - 2⁵ = 817312649 is a prime.

It is a super-2 number, since 2×817312681² = 1336000037046815522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 817312681.

It is not a weakly prime, because it can be changed into another prime (817312687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408656340 + 408656341.

It is an arithmetic number, because the mean of its divisors is an integer number (408656341).

Almost surely, 2^817312681 is an apocalyptic number.

It is an amenable number.

817312681 is a deficient number, since it is larger than the sum of its proper divisors (1).

817312681 is an equidigital number, since it uses as much as digits as its factorization.

817312681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 37.

The square root of 817312681 is about 28588.6809944076. The cubic root of 817312681 is about 934.9665619506.

The spelling of 817312681 in words is "eight hundred seventeen million, three hundred twelve thousand, six hundred eighty-one".