18355139 has 4 divisors (see below), whose sum is σ = 20023800. Its totient is φ = 16686480.

The previous prime is 18355111. The next prime is 18355151. The reversal of 18355139 is 93155381.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18355139 - 2¹² = 18351043 is a prime.

It is a super-2 number, since 2×18355139² = 673822255418642, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18355099 and 18355108.

It is not an unprimeable number, because it can be changed into a prime (18355199) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 834314 + ... + 834335.

It is an arithmetic number, because the mean of its divisors is an integer number (5005950).

Almost surely, 2^18355139 is an apocalyptic number.

18355139 is a deficient number, since it is larger than the sum of its proper divisors (1668661).

18355139 is a wasteful number, since it uses less digits than its factorization.

18355139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1668660.

The product of its digits is 16200, while the sum is 35.

The square root of 18355139 is about 4284.2897894517. The cubic root of 18355139 is about 263.7864961513.

The spelling of 18355139 in words is "eighteen million, three hundred fifty-five thousand, one hundred thirty-nine".