18421438 has 48 divisors (see below), whose sum is σ = 34924320. Its totient is φ = 7128576.

The previous prime is 18421433. The next prime is 18421439. The reversal of 18421438 is 83412481.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18421433) 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 23 ways as a sum of consecutive naturals, for example, 117256 + ... + 117412.

It is an arithmetic number, because the mean of its divisors is an integer number (727590).

Almost surely, 2^18421438 is an apocalyptic number.

18421438 is a deficient number, since it is larger than the sum of its proper divisors (16502882).

18421438 is a wasteful number, since it uses less digits than its factorization.

18421438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229 (or 212 counting only the distinct ones).

The product of its digits is 6144, while the sum is 31.

The square root of 18421438 is about 4292.0202702224. The cubic root of 18421438 is about 264.1037146061.

The spelling of 18421438 in words is "eighteen million, four hundred twenty-one thousand, four hundred thirty-eight".