18748391 has 2 divisors, whose sum is σ = 18748392. Its totient is φ = 18748390.

The previous prime is 18748363. The next prime is 18748403. The reversal of 18748391 is 19384781.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18748391 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18748351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9374195 + 9374196.

It is an arithmetic number, because the mean of its divisors is an integer number (9374196).

Almost surely, 2^18748391 is an apocalyptic number.

18748391 is a deficient number, since it is larger than the sum of its proper divisors (1).

18748391 is an equidigital number, since it uses as much as digits as its factorization.

18748391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 41.

The square root of 18748391 is about 4329.9412236196. The cubic root of 18748391 is about 265.6570428888.

The spelling of 18748391 in words is "eighteen million, seven hundred forty-eight thousand, three hundred ninety-one".