18891143 has 2 divisors, whose sum is σ = 18891144. Its totient is φ = 18891142.

The previous prime is 18891137. The next prime is 18891193. The reversal of 18891143 is 34119881.

It is a weak prime.

It is an emirp because it is prime and its reverse (34119881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18891143 - 2⁶ = 18891079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18891113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9445571 + 9445572.

It is an arithmetic number, because the mean of its divisors is an integer number (9445572).

Almost surely, 2^18891143 is an apocalyptic number.

18891143 is a deficient number, since it is larger than the sum of its proper divisors (1).

18891143 is an equidigital number, since it uses as much as digits as its factorization.

18891143 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 18891143 is about 4346.3942527111. The cubic root of 18891143 is about 266.3295846788.

The spelling of 18891143 in words is "eighteen million, eight hundred ninety-one thousand, one hundred forty-three".