866121647 has 2 divisors, whose sum is σ = 866121648. Its totient is φ = 866121646.

The previous prime is 866121589. The next prime is 866121671. The reversal of 866121647 is 746121668.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 866121647 - 2⁶ = 866121583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866121677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433060823 + 433060824.

It is an arithmetic number, because the mean of its divisors is an integer number (433060824).

Almost surely, 2^866121647 is an apocalyptic number.

866121647 is a deficient number, since it is larger than the sum of its proper divisors (1).

866121647 is an equidigital number, since it uses as much as digits as its factorization.

866121647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 41.

The square root of 866121647 is about 29429.9447332135. The cubic root of 866121647 is about 953.2196014774.

The spelling of 866121647 in words is "eight hundred sixty-six million, one hundred twenty-one thousand, six hundred forty-seven".