18863909 has 2 divisors, whose sum is σ = 18863910. Its totient is φ = 18863908.

The previous prime is 18863879. The next prime is 18863951. The reversal of 18863909 is 90936881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18515809 + 348100 = 4303^2 + 590^2 .

It is a cyclic number.

It is not a de Polignac number, because 18863909 - 2⁸ = 18863653 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18863909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18863959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9431954 + 9431955.

It is an arithmetic number, because the mean of its divisors is an integer number (9431955).

Almost surely, 2^18863909 is an apocalyptic number.

It is an amenable number.

18863909 is a deficient number, since it is larger than the sum of its proper divisors (1).

18863909 is an equidigital number, since it uses as much as digits as its factorization.

18863909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 44.

The square root of 18863909 is about 4343.2601810161. The cubic root of 18863909 is about 266.2015404028.

The spelling of 18863909 in words is "eighteen million, eight hundred sixty-three thousand, nine hundred nine".