18997427 has 2 divisors, whose sum is σ = 18997428. Its totient is φ = 18997426.

The previous prime is 18997421. The next prime is 18997439. The reversal of 18997427 is 72479981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18997427 - 2⁴ = 18997411 is a prime.

It is not a weakly prime, because it can be changed into another prime (18997421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9498713 + 9498714.

It is an arithmetic number, because the mean of its divisors is an integer number (9498714).

Almost surely, 2^18997427 is an apocalyptic number.

18997427 is a deficient number, since it is larger than the sum of its proper divisors (1).

18997427 is an equidigital number, since it uses as much as digits as its factorization.

18997427 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 254016, while the sum is 47.

The square root of 18997427 is about 4358.6037902062. The cubic root of 18997427 is about 266.8281190698.

The spelling of 18997427 in words is "eighteen million, nine hundred ninety-seven thousand, four hundred twenty-seven".