18121279 has 4 divisors (see below), whose sum is σ = 19768680. Its totient is φ = 16473880.

The previous prime is 18121261. The next prime is 18121297. The reversal of 18121279 is 97212181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97212181 = 11 ⋅8837471.

It is an interprime number because it is at equal distance from previous prime (18121261) and next prime (18121297).

It is a cyclic number.

It is not a de Polignac number, because 18121279 - 2⁷ = 18121151 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18121279.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18121979) 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, 823684 + ... + 823705.

It is an arithmetic number, because the mean of its divisors is an integer number (4942170).

Almost surely, 2^18121279 is an apocalyptic number.

18121279 is a deficient number, since it is larger than the sum of its proper divisors (1647401).

18121279 is a wasteful number, since it uses less digits than its factorization.

18121279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1647400.

The product of its digits is 2016, while the sum is 31.

The square root of 18121279 is about 4256.9095597628. The cubic root of 18121279 is about 262.6614166698.

The spelling of 18121279 in words is "eighteen million, one hundred twenty-one thousand, two hundred seventy-nine".