18831121 has 8 divisors (see below), whose sum is σ = 20626920. Its totient is φ = 17111808.

The previous prime is 18831107. The next prime is 18831139. The reversal of 18831121 is 12113881.

It can be written as a sum of positive squares in 4 ways, for example, as 3900625 + 14930496 = 1975^2 + 3864^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18831121 - 2¹¹ = 18829073 is a prime.

It is a super-2 number, since 2×18831121² = 709222236233282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18831191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18606 + ... + 19591.

It is an arithmetic number, because the mean of its divisors is an integer number (2578365).

Almost surely, 2^18831121 is an apocalyptic number.

It is an amenable number.

18831121 is a deficient number, since it is larger than the sum of its proper divisors (1795799).

18831121 is a wasteful number, since it uses less digits than its factorization.

18831121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38243.

The product of its digits is 384, while the sum is 25.

The square root of 18831121 is about 4339.4839554952. The cubic root of 18831121 is about 266.0472196497.

The spelling of 18831121 in words is "eighteen million, eight hundred thirty-one thousand, one hundred twenty-one".