18789121 has 4 divisors (see below), whose sum is σ = 20234452. Its totient is φ = 17343792.

The previous prime is 18789109. The next prime is 18789149. The reversal of 18789121 is 12198781.

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 12215025 + 6574096 = 3495^2 + 2564^2 .

It is a cyclic number.

It is not a de Polignac number, because 18789121 - 2²³ = 10400513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18789101) 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, 722646 + ... + 722671.

It is an arithmetic number, because the mean of its divisors is an integer number (5058613).

Almost surely, 2^18789121 is an apocalyptic number.

It is an amenable number.

18789121 is a deficient number, since it is larger than the sum of its proper divisors (1445331).

18789121 is a wasteful number, since it uses less digits than its factorization.

18789121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1445330.

The product of its digits is 8064, while the sum is 37.

The square root of 18789121 is about 4334.6419690673. The cubic root of 18789121 is about 265.8492795689.

The spelling of 18789121 in words is "eighteen million, seven hundred eighty-nine thousand, one hundred twenty-one".