811997 has 2 divisors, whose sum is σ = 811998. Its totient is φ = 811996.

The previous prime is 811991. The next prime is 812011. The reversal of 811997 is 799118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 811801 + 196 = 901^2 + 14^2 .

It is a cyclic number.

It is not a de Polignac number, because 811997 - 2⁴ = 811981 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 (811991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405998 + 405999.

It is an arithmetic number, because the mean of its divisors is an integer number (405999).

2⁸¹¹⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

811997 is a deficient number, since it is larger than the sum of its proper divisors (1).

811997 is an equidigital number, since it uses as much as digits as its factorization.

811997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 35.

The square root of 811997 is about 901.1087614711. The cubic root of 811997 is about 93.2935190161.

The spelling of 811997 in words is "eight hundred eleven thousand, nine hundred ninety-seven".