18668861 has 2 divisors, whose sum is σ = 18668862. Its totient is φ = 18668860.

The previous prime is 18668857. The next prime is 18668921. The reversal of 18668861 is 16886681.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17480761 + 1188100 = 4181^2 + 1090^2 .

It is a cyclic number.

It is not a de Polignac number, because 18668861 - 2² = 18668857 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18668821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9334430 + 9334431.

It is an arithmetic number, because the mean of its divisors is an integer number (9334431).

Almost surely, 2^18668861 is an apocalyptic number.

It is an amenable number.

18668861 is a deficient number, since it is larger than the sum of its proper divisors (1).

18668861 is an equidigital number, since it uses as much as digits as its factorization.

18668861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 110592, while the sum is 44.

The square root of 18668861 is about 4320.7477362142. The cubic root of 18668861 is about 265.2808746166.

The spelling of 18668861 in words is "eighteen million, six hundred sixty-eight thousand, eight hundred sixty-one".