18828391 has 2 divisors, whose sum is σ = 18828392. Its totient is φ = 18828390.

The previous prime is 18828371. The next prime is 18828427. The reversal of 18828391 is 19382881.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18828391 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 (18828361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9414195 + 9414196.

It is an arithmetic number, because the mean of its divisors is an integer number (9414196).

Almost surely, 2^18828391 is an apocalyptic number.

18828391 is a deficient number, since it is larger than the sum of its proper divisors (1).

18828391 is an equidigital number, since it uses as much as digits as its factorization.

18828391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 40.

The square root of 18828391 is about 4339.1693905631. The cubic root of 18828391 is about 266.0343624932.

The spelling of 18828391 in words is "eighteen million, eight hundred twenty-eight thousand, three hundred ninety-one".