18663257 has 2 divisors, whose sum is σ = 18663258. Its totient is φ = 18663256.

The previous prime is 18663233. The next prime is 18663283. The reversal of 18663257 is 75236681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18139081 + 524176 = 4259^2 + 724^2 .

It is a cyclic number.

It is not a de Polignac number, because 18663257 - 2¹⁰ = 18662233 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 18663257.

It is not a weakly prime, because it can be changed into another prime (18663217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9331628 + 9331629.

It is an arithmetic number, because the mean of its divisors is an integer number (9331629).

Almost surely, 2^18663257 is an apocalyptic number.

It is an amenable number.

18663257 is a deficient number, since it is larger than the sum of its proper divisors (1).

18663257 is an equidigital number, since it uses as much as digits as its factorization.

18663257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 38.

The square root of 18663257 is about 4320.0991886761. The cubic root of 18663257 is about 265.2543280444.

The spelling of 18663257 in words is "eighteen million, six hundred sixty-three thousand, two hundred fifty-seven".