863891881 has 2 divisors, whose sum is σ = 863891882. Its totient is φ = 863891880.

The previous prime is 863891851. The next prime is 863891909. The reversal of 863891881 is 188198368.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 859955625 + 3936256 = 29325^2 + 1984^2 .

It is a cyclic number.

It is not a de Polignac number, because 863891881 - 2²³ = 855503273 is a prime.

It is a super-2 number, since 2×863891881² = 1492618364115436322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (863891851) 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, 431945940 + 431945941.

It is an arithmetic number, because the mean of its divisors is an integer number (431945941).

Almost surely, 2^863891881 is an apocalyptic number.

It is an amenable number.

863891881 is a deficient number, since it is larger than the sum of its proper divisors (1).

863891881 is an equidigital number, since it uses as much as digits as its factorization.

863891881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 663552, while the sum is 52.

The square root of 863891881 is about 29392.0377143198. The cubic root of 863891881 is about 952.4009007703.

The spelling of 863891881 in words is "eight hundred sixty-three million, eight hundred ninety-one thousand, eight hundred eighty-one".