18421109 has 12 divisors (see below), whose sum is σ = 21631500. Its totient is φ = 15640128.

The previous prime is 18421097. The next prime is 18421111. The reversal of 18421109 is 90112481.

It can be written as a sum of positive squares in 2 ways, for example, as 4708900 + 13712209 = 2170^2 + 3703^2 .

It is not a de Polignac number, because 18421109 - 2⁴ = 18421093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18421129) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3617 + ... + 7065.

It is an arithmetic number, because the mean of its divisors is an integer number (1802625).

Almost surely, 2^18421109 is an apocalyptic number.

It is an amenable number.

18421109 is a deficient number, since it is larger than the sum of its proper divisors (3210391).

18421109 is a wasteful number, since it uses less digits than its factorization.

18421109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3572 (or 3565 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 18421109 is about 4291.9819431121. The cubic root of 18421109 is about 264.1021423322.

It can be divided in two parts, 18421 and 109, that multiplied together give a square (2007889 = 1417²).

The spelling of 18421109 in words is "eighteen million, four hundred twenty-one thousand, one hundred nine".