863891909 has 2 divisors, whose sum is σ = 863891910. Its totient is φ = 863891908.

The previous prime is 863891881. The next prime is 863891921. The reversal of 863891909 is 909198368.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 857904100 + 5987809 = 29290^2 + 2447^2 .

It is a cyclic number.

It is not a de Polignac number, because 863891909 - 2⁸ = 863891653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (863891929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 431945954 + 431945955.

It is an arithmetic number, because the mean of its divisors is an integer number (431945955).

Almost surely, 2^863891909 is an apocalyptic number.

It is an amenable number.

863891909 is a deficient number, since it is larger than the sum of its proper divisors (1).

863891909 is an equidigital number, since it uses as much as digits as its factorization.

863891909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 839808, while the sum is 53.

The square root of 863891909 is about 29392.0381906393. The cubic root of 863891909 is about 952.4009110599.

The spelling of 863891909 in words is "eight hundred sixty-three million, eight hundred ninety-one thousand, nine hundred nine".