812681 has 2 divisors, whose sum is σ = 812682. Its totient is φ = 812680.

The previous prime is 812671. The next prime is 812689. The reversal of 812681 is 186218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 614656 + 198025 = 784^2 + 445^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-812681 is a prime.

It is a super-2 number, since 2×812681² = 1320900815522, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 812681.

It is not a weakly prime, because it can be changed into another prime (812689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406340 + 406341.

It is an arithmetic number, because the mean of its divisors is an integer number (406341).

2⁸¹²⁶⁸¹ is an apocalyptic number.

It is an amenable number.

812681 is a deficient number, since it is larger than the sum of its proper divisors (1).

812681 is an equidigital number, since it uses as much as digits as its factorization.

812681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 768, while the sum is 26.

The square root of 812681 is about 901.4882140106. The cubic root of 812681 is about 93.3197074780.

Adding to 812681 its reverse (186218), we get a palindrome (998899).

The spelling of 812681 in words is "eight hundred twelve thousand, six hundred eighty-one".