18123913 has 4 divisors (see below), whose sum is σ = 18245700. Its totient is φ = 18002128.

The previous prime is 18123901. The next prime is 18123947. The reversal of 18123913 is 31932181.

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

It can be written as a sum of positive squares in 2 ways, for example, as 751689 + 17372224 = 867^2 + 4168^2 .

It is a cyclic number.

It is not a de Polignac number, because 18123913 - 2⁵ = 18123881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18123953) 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, 60670 + ... + 60967.

It is an arithmetic number, because the mean of its divisors is an integer number (4561425).

Almost surely, 2^18123913 is an apocalyptic number.

It is an amenable number.

18123913 is a deficient number, since it is larger than the sum of its proper divisors (121787).

18123913 is a wasteful number, since it uses less digits than its factorization.

18123913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121786.

The product of its digits is 1296, while the sum is 28.

The square root of 18123913 is about 4257.2189278918. The cubic root of 18123913 is about 262.6741423472.

The spelling of 18123913 in words is "eighteen million, one hundred twenty-three thousand, nine hundred thirteen".