18945139 has 2 divisors, whose sum is σ = 18945140. Its totient is φ = 18945138.

The previous prime is 18945131. The next prime is 18945151. The reversal of 18945139 is 93154981.

It is a weak prime.

It is an emirp because it is prime and its reverse (93154981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18945139 - 2³ = 18945131 is a prime.

It is not a weakly prime, because it can be changed into another prime (18945131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9472569 + 9472570.

It is an arithmetic number, because the mean of its divisors is an integer number (9472570).

Almost surely, 2^18945139 is an apocalyptic number.

18945139 is a deficient number, since it is larger than the sum of its proper divisors (1).

18945139 is an equidigital number, since it uses as much as digits as its factorization.

18945139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 40.

The square root of 18945139 is about 4352.6014060559. The cubic root of 18945139 is about 266.5830906494.

The spelling of 18945139 in words is "eighteen million, nine hundred forty-five thousand, one hundred thirty-nine".