811806857 has 2 divisors, whose sum is σ = 811806858. Its totient is φ = 811806856.

The previous prime is 811806851. The next prime is 811806881. The reversal of 811806857 is 758608118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 493683961 + 318122896 = 22219^2 + 17836^2 .

It is a cyclic number.

It is not a de Polignac number, because 811806857 - 2²⁰ = 810758281 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (811806851) 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 as a sum of consecutive naturals, namely, 405903428 + 405903429.

It is an arithmetic number, because the mean of its divisors is an integer number (405903429).

Almost surely, 2^811806857 is an apocalyptic number.

It is an amenable number.

811806857 is a deficient number, since it is larger than the sum of its proper divisors (1).

811806857 is an equidigital number, since it uses as much as digits as its factorization.

811806857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 107520, while the sum is 44.

The square root of 811806857 is about 28492.2245007300. The cubic root of 811806857 is about 932.8623635600.

The spelling of 811806857 in words is "eight hundred eleven million, eight hundred six thousand, eight hundred fifty-seven".