18813438 has 64 divisors (see below), whose sum is σ = 48522240. Its totient is φ = 5292000.

The previous prime is 18813419. The next prime is 18813449. The reversal of 18813438 is 83431881.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26488 + ... + 27188.

It is an arithmetic number, because the mean of its divisors is an integer number (758160).

Almost surely, 2^18813438 is an apocalyptic number.

18813438 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18813438, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24261120).

18813438 is an abundant number, since it is smaller than the sum of its proper divisors (29708802).

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

18813438 is a wasteful number, since it uses less digits than its factorization.

18813438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 790 (or 784 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 18813438 is about 4337.4460227189. The cubic root of 18813438 is about 265.9639180711.

The spelling of 18813438 in words is "eighteen million, eight hundred thirteen thousand, four hundred thirty-eight".