18438420 has 192 divisors, whose sum is σ = 69543936. Its totient is φ = 3525120.

The previous prime is 18438391. The next prime is 18438437. The reversal of 18438420 is 2483481.

18438420 is nontrivially palindromic in base 9.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 59907 + ... + 60213.

It is an arithmetic number, because the mean of its divisors is an integer number (362208).

Almost surely, 2^18438420 is an apocalyptic number.

18438420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18438420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34771968).

18438420 is an abundant number, since it is smaller than the sum of its proper divisors (51105516).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18438420 is a wasteful number, since it uses less digits than its factorization.

18438420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350 (or 348 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 18438420 is about 4293.9981369349. The cubic root of 18438420 is about 264.1848452938.

The spelling of 18438420 in words is "eighteen million, four hundred thirty-eight thousand, four hundred twenty".