18738919 has 2 divisors, whose sum is σ = 18738920. Its totient is φ = 18738918.

The previous prime is 18738917. The next prime is 18738943. The reversal of 18738919 is 91983781.

It is a weak prime.

It is an emirp because it is prime and its reverse (91983781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18738919 - 2¹ = 18738917 is a prime.

It is a super-2 number, since 2×18738919² = 702294170577122, which contains 22 as substring.

Together with 18738917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18738917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9369459 + 9369460.

It is an arithmetic number, because the mean of its divisors is an integer number (9369460).

Almost surely, 2^18738919 is an apocalyptic number.

18738919 is a deficient number, since it is larger than the sum of its proper divisors (1).

18738919 is an equidigital number, since it uses as much as digits as its factorization.

18738919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 46.

The square root of 18738919 is about 4328.8473061544. The cubic root of 18738919 is about 265.6122972288.

The spelling of 18738919 in words is "eighteen million, seven hundred thirty-eight thousand, nine hundred nineteen".