811625891 has 2 divisors, whose sum is σ = 811625892. Its totient is φ = 811625890.

The previous prime is 811625861. The next prime is 811625897. The reversal of 811625891 is 198526118.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 811625891 - 2¹⁰ = 811624867 is a prime.

It is not a weakly prime, because it can be changed into another prime (811625897) 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, 405812945 + 405812946.

It is an arithmetic number, because the mean of its divisors is an integer number (405812946).

Almost surely, 2^811625891 is an apocalyptic number.

811625891 is a deficient number, since it is larger than the sum of its proper divisors (1).

811625891 is an equidigital number, since it uses as much as digits as its factorization.

811625891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 41.

The square root of 811625891 is about 28489.0486152135. The cubic root of 811625891 is about 932.7930412762.

The spelling of 811625891 in words is "eight hundred eleven million, six hundred twenty-five thousand, eight hundred ninety-one".