866643091 has 2 divisors, whose sum is σ = 866643092. Its totient is φ = 866643090.

The previous prime is 866643083. The next prime is 866643149. The reversal of 866643091 is 190346668.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 866643091 - 2³ = 866643083 is a prime.

It is not a weakly prime, because it can be changed into another prime (866643031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433321545 + 433321546.

It is an arithmetic number, because the mean of its divisors is an integer number (433321546).

Almost surely, 2^866643091 is an apocalyptic number.

866643091 is a deficient number, since it is larger than the sum of its proper divisors (1).

866643091 is an equidigital number, since it uses as much as digits as its factorization.

866643091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 186624, while the sum is 43.

The square root of 866643091 is about 29438.8024722474. The cubic root of 866643091 is about 953.4108567236.

The spelling of 866643091 in words is "eight hundred sixty-six million, six hundred forty-three thousand, ninety-one".