18438920 has 16 divisors (see below), whose sum is σ = 41487660. Its totient is φ = 7375552.

The previous prime is 18438919. The next prime is 18438923. The reversal of 18438920 is 2983481.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18438436 + 484 = 4294^2 + 22^2 .

It is not an unprimeable number, because it can be changed into a prime (18438923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 230447 + ... + 230526.

Almost surely, 2^18438920 is an apocalyptic number.

18438920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18438920 is an abundant number, since it is smaller than the sum of its proper divisors (23048740).

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

18438920 is a wasteful number, since it uses less digits than its factorization.

18438920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460984 (or 460980 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 18438920 is about 4294.0563573386. The cubic root of 18438920 is about 264.1872332647.

The spelling of 18438920 in words is "eighteen million, four hundred thirty-eight thousand, nine hundred twenty".