866363891 has 2 divisors, whose sum is σ = 866363892. Its totient is φ = 866363890.

The previous prime is 866363879. The next prime is 866363929. The reversal of 866363891 is 198363668.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 866363891 - 2²² = 862169587 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (866363821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433181945 + 433181946.

It is an arithmetic number, because the mean of its divisors is an integer number (433181946).

Almost surely, 2^866363891 is an apocalyptic number.

866363891 is a deficient number, since it is larger than the sum of its proper divisors (1).

866363891 is an equidigital number, since it uses as much as digits as its factorization.

866363891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1119744, while the sum is 50.

The square root of 866363891 is about 29434.0600495412. The cubic root of 866363891 is about 953.3084612835.

The spelling of 866363891 in words is "eight hundred sixty-six million, three hundred sixty-three thousand, eight hundred ninety-one".