18238739 has 4 divisors (see below), whose sum is σ = 19311624. Its totient is φ = 17165856.

The previous prime is 18238711. The next prime is 18238771. The reversal of 18238739 is 93783281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93783281 = 307 ⋅305483.

It is a cyclic number.

It is not a de Polignac number, because 18238739 - 2⁸ = 18238483 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18238696 and 18238705.

It is not an unprimeable number, because it can be changed into a prime (18238789) 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 in 3 ways as a sum of consecutive naturals, for example, 536417 + ... + 536450.

It is an arithmetic number, because the mean of its divisors is an integer number (4827906).

Almost surely, 2^18238739 is an apocalyptic number.

18238739 is a deficient number, since it is larger than the sum of its proper divisors (1072885).

18238739 is a wasteful number, since it uses less digits than its factorization.

18238739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1072884.

The product of its digits is 72576, while the sum is 41.

The square root of 18238739 is about 4270.6836689223. The cubic root of 18238739 is about 263.2277083553.

The spelling of 18238739 in words is "eighteen million, two hundred thirty-eight thousand, seven hundred thirty-nine".