18938317 has 4 divisors (see below), whose sum is σ = 19197820. Its totient is φ = 18678816.

The previous prime is 18938299. The next prime is 18938419. The reversal of 18938317 is 71383981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71383981 = 6449 ⋅11069.

It can be written as a sum of positive squares in 2 ways, for example, as 6869641 + 12068676 = 2621^2 + 3474^2 .

It is a cyclic number.

It is not a de Polignac number, because 18938317 - 2¹⁹ = 18414029 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18938317.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18938617) 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 in 3 ways as a sum of consecutive naturals, for example, 129642 + ... + 129787.

It is an arithmetic number, because the mean of its divisors is an integer number (4799455).

Almost surely, 2^18938317 is an apocalyptic number.

It is an amenable number.

18938317 is a deficient number, since it is larger than the sum of its proper divisors (259503).

18938317 is an equidigital number, since it uses as much as digits as its factorization.

18938317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259502.

The product of its digits is 36288, while the sum is 40.

The square root of 18938317 is about 4351.8176662172. The cubic root of 18938317 is about 266.5510886290.

The spelling of 18938317 in words is "eighteen million, nine hundred thirty-eight thousand, three hundred seventeen".