18815663 has 2 divisors, whose sum is σ = 18815664. Its totient is φ = 18815662.

The previous prime is 18815659. The next prime is 18815669. The reversal of 18815663 is 36651881.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18815663 - 2² = 18815659 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18815669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9407831 + 9407832.

It is an arithmetic number, because the mean of its divisors is an integer number (9407832).

Almost surely, 2^18815663 is an apocalyptic number.

18815663 is a deficient number, since it is larger than the sum of its proper divisors (1).

18815663 is an equidigital number, since it uses as much as digits as its factorization.

18815663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 38.

The square root of 18815663 is about 4337.7025024776. The cubic root of 18815663 is about 265.9744025343.

It can be divided in two parts, 188 and 15663, that added together give a palindrome (15851).

The spelling of 18815663 in words is "eighteen million, eight hundred fifteen thousand, six hundred sixty-three".