18918143 has 2 divisors, whose sum is σ = 18918144. Its totient is φ = 18918142.

The previous prime is 18918139. The next prime is 18918157. The reversal of 18918143 is 34181981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18918143 - 2² = 18918139 is a prime.

It is a super-2 number, since 2×18918143² = 715792269136898, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18918043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9459071 + 9459072.

It is an arithmetic number, because the mean of its divisors is an integer number (9459072).

Almost surely, 2^18918143 is an apocalyptic number.

18918143 is a deficient number, since it is larger than the sum of its proper divisors (1).

18918143 is an equidigital number, since it uses as much as digits as its factorization.

18918143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 35.

The square root of 18918143 is about 4349.4991665708. The cubic root of 18918143 is about 266.4564073502.

The spelling of 18918143 in words is "eighteen million, nine hundred eighteen thousand, one hundred forty-three".