812172857 has 2 divisors, whose sum is σ = 812172858. Its totient is φ = 812172856.

The previous prime is 812172847. The next prime is 812172859. The reversal of 812172857 is 758271218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 431766841 + 380406016 = 20779^2 + 19504^2 .

It is a cyclic number.

It is not a de Polignac number, because 812172857 - 2¹⁶ = 812107321 is a prime.

Together with 812172859, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (812172859) 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, 406086428 + 406086429.

It is an arithmetic number, because the mean of its divisors is an integer number (406086429).

Almost surely, 2^812172857 is an apocalyptic number.

It is an amenable number.

812172857 is a deficient number, since it is larger than the sum of its proper divisors (1).

812172857 is an equidigital number, since it uses as much as digits as its factorization.

812172857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62720, while the sum is 41.

The square root of 812172857 is about 28498.6465818993. The cubic root of 812172857 is about 933.0025349667.

The spelling of 812172857 in words is "eight hundred twelve million, one hundred seventy-two thousand, eight hundred fifty-seven".