866610391 has 2 divisors, whose sum is σ = 866610392. Its totient is φ = 866610390.

The previous prime is 866610359. The next prime is 866610419. The reversal of 866610391 is 193016668.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 866610391 - 2⁵ = 866610359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866610331) 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, 433305195 + 433305196.

It is an arithmetic number, because the mean of its divisors is an integer number (433305196).

Almost surely, 2^866610391 is an apocalyptic number.

866610391 is a deficient number, since it is larger than the sum of its proper divisors (1).

866610391 is an equidigital number, since it uses as much as digits as its factorization.

866610391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 866610391 is about 29438.2470775690. The cubic root of 866610391 is about 953.3988652715.

The spelling of 866610391 in words is "eight hundred sixty-six million, six hundred ten thousand, three hundred ninety-one".