811828781 has 2 divisors, whose sum is σ = 811828782. Its totient is φ = 811828780.

The previous prime is 811828757. The next prime is 811828783. The reversal of 811828781 is 187828118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 774508900 + 37319881 = 27830^2 + 6109^2 .

It is a cyclic number.

It is not a de Polignac number, because 811828781 - 2²⁶ = 744719917 is a prime.

It is a super-2 number, since 2×811828781² = 1318131939319891922, which contains 22 as substring.

Together with 811828783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (811828783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405914390 + 405914391.

It is an arithmetic number, because the mean of its divisors is an integer number (405914391).

Almost surely, 2^811828781 is an apocalyptic number.

It is an amenable number.

811828781 is a deficient number, since it is larger than the sum of its proper divisors (1).

811828781 is an equidigital number, since it uses as much as digits as its factorization.

811828781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 57344, while the sum is 44.

The square root of 811828781 is about 28492.6092346770. The cubic root of 811828781 is about 932.8707612432.

The spelling of 811828781 in words is "eight hundred eleven million, eight hundred twenty-eight thousand, seven hundred eighty-one".