18988393 has 2 divisors, whose sum is σ = 18988394. Its totient is φ = 18988392.

The previous prime is 18988367. The next prime is 18988421. The reversal of 18988393 is 39388981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17614809 + 1373584 = 4197^2 + 1172^2 .

It is a cyclic number.

It is not a de Polignac number, because 18988393 - 2²¹ = 16891241 is a prime.

It is not a weakly prime, because it can be changed into another prime (18988313) 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, 9494196 + 9494197.

It is an arithmetic number, because the mean of its divisors is an integer number (9494197).

Almost surely, 2^18988393 is an apocalyptic number.

It is an amenable number.

18988393 is a deficient number, since it is larger than the sum of its proper divisors (1).

18988393 is an equidigital number, since it uses as much as digits as its factorization.

18988393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 373248, while the sum is 49.

The square root of 18988393 is about 4357.5673259285. The cubic root of 18988393 is about 266.7858167196.

The spelling of 18988393 in words is "eighteen million, nine hundred eighty-eight thousand, three hundred ninety-three".