18988217 has 2 divisors, whose sum is σ = 18988218. Its totient is φ = 18988216.

The previous prime is 18988199. The next prime is 18988219. The reversal of 18988217 is 71288981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16152361 + 2835856 = 4019^2 + 1684^2 .

It is a cyclic number.

It is not a de Polignac number, because 18988217 - 2¹⁴ = 18971833 is a prime.

Together with 18988219, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18988219) 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, 9494108 + 9494109.

It is an arithmetic number, because the mean of its divisors is an integer number (9494109).

Almost surely, 2^18988217 is an apocalyptic number.

It is an amenable number.

18988217 is a deficient number, since it is larger than the sum of its proper divisors (1).

18988217 is an equidigital number, since it uses as much as digits as its factorization.

18988217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 44.

The square root of 18988217 is about 4357.5471311278. The cubic root of 18988217 is about 266.7849924538.

The spelling of 18988217 in words is "eighteen million, nine hundred eighty-eight thousand, two hundred seventeen".