18739939 has 2 divisors, whose sum is σ = 18739940. Its totient is φ = 18739938.

The previous prime is 18739937. The next prime is 18739949. The reversal of 18739939 is 93993781.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18739939 - 2¹ = 18739937 is a prime.

Together with 18739937, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 18739892 and 18739901.

It is not a weakly prime, because it can be changed into another prime (18739937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9369969 + 9369970.

It is an arithmetic number, because the mean of its divisors is an integer number (9369970).

Almost surely, 2^18739939 is an apocalyptic number.

18739939 is a deficient number, since it is larger than the sum of its proper divisors (1).

18739939 is an equidigital number, since it uses as much as digits as its factorization.

18739939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 367416, while the sum is 49.

The square root of 18739939 is about 4328.9651188246. The cubic root of 18739939 is about 265.6171164258.

The spelling of 18739939 in words is "eighteen million, seven hundred thirty-nine thousand, nine hundred thirty-nine".