811795981 has 4 divisors (see below), whose sum is σ = 811899712. Its totient is φ = 811692252.

The previous prime is 811795961. The next prime is 811796003. The reversal of 811795981 is 189597118.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 811795981 - 2¹¹ = 811793933 is a prime.

It is a super-2 number, since 2×811795981² = 1318025429535504722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811795961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39075 + ... + 56128.

It is an arithmetic number, because the mean of its divisors is an integer number (202974928).

Almost surely, 2^811795981 is an apocalyptic number.

It is an amenable number.

811795981 is a deficient number, since it is larger than the sum of its proper divisors (103731).

811795981 is an equidigital number, since it uses as much as digits as its factorization.

811795981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103730.

The product of its digits is 181440, while the sum is 49.

The square root of 811795981 is about 28492.0336410022. The cubic root of 811795981 is about 932.8581976034.

The spelling of 811795981 in words is "eight hundred eleven million, seven hundred ninety-five thousand, nine hundred eighty-one".