809875813 has 2 divisors, whose sum is σ = 809875814. Its totient is φ = 809875812.

The previous prime is 809875783. The next prime is 809875841. The reversal of 809875813 is 318578908.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 596189889 + 213685924 = 24417^2 + 14618^2 .

It is a cyclic number.

It is not a de Polignac number, because 809875813 - 2²¹ = 807778661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809875853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404937906 + 404937907.

It is an arithmetic number, because the mean of its divisors is an integer number (404937907).

Almost surely, 2^809875813 is an apocalyptic number.

It is an amenable number.

809875813 is a deficient number, since it is larger than the sum of its proper divisors (1).

809875813 is an equidigital number, since it uses as much as digits as its factorization.

809875813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 483840, while the sum is 49.

The square root of 809875813 is about 28458.3171146855. The cubic root of 809875813 is about 932.1221101065.

The spelling of 809875813 in words is "eight hundred nine million, eight hundred seventy-five thousand, eight hundred thirteen".