864331891 has 2 divisors, whose sum is σ = 864331892. Its totient is φ = 864331890.

The previous prime is 864331873. The next prime is 864331903. The reversal of 864331891 is 198133468.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 864331891 - 2¹⁷ = 864200819 is a prime.

It is not a weakly prime, because it can be changed into another prime (864335891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432165945 + 432165946.

It is an arithmetic number, because the mean of its divisors is an integer number (432165946).

Almost surely, 2^864331891 is an apocalyptic number.

864331891 is a deficient number, since it is larger than the sum of its proper divisors (1).

864331891 is an equidigital number, since it uses as much as digits as its factorization.

864331891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416, while the sum is 43.

The square root of 864331891 is about 29399.5219518957. The cubic root of 864331891 is about 952.5625702266.

The spelling of 864331891 in words is "eight hundred sixty-four million, three hundred thirty-one thousand, eight hundred ninety-one".