800636861 has 2 divisors, whose sum is σ = 800636862. Its totient is φ = 800636860.

The previous prime is 800636717. The next prime is 800636891. The reversal of 800636861 is 168636008.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 542424100 + 258212761 = 23290^2 + 16069^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-800636861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (800636891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 400318430 + 400318431.

It is an arithmetic number, because the mean of its divisors is an integer number (400318431).

Almost surely, 2^800636861 is an apocalyptic number.

It is an amenable number.

800636861 is a deficient number, since it is larger than the sum of its proper divisors (1).

800636861 is an equidigital number, since it uses as much as digits as its factorization.

800636861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 800636861 is about 28295.5272260476. The cubic root of 800636861 is about 928.5640386259.

The spelling of 800636861 in words is "eight hundred million, six hundred thirty-six thousand, eight hundred sixty-one".