18115400 has 48 divisors (see below), whose sum is σ = 42938100. Its totient is φ = 7105280.

The previous prime is 18115381. The next prime is 18115403. The reversal of 18115400 is 451181.

It can be written as a sum of positive squares in 6 ways, for example, as 5597956 + 12517444 = 2366^2 + 3538^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (18115403) 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, 9746 + ... + 11454.

Almost surely, 2^18115400 is an apocalyptic number.

18115400 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 18115400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21469050).

18115400 is an abundant number, since it is smaller than the sum of its proper divisors (24822700).

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

18115400 is a wasteful number, since it uses less digits than its factorization.

18115400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1778 (or 1769 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 20.

The square root of 18115400 is about 4256.2189793290. The cubic root of 18115400 is about 262.6330089345.

Adding to 18115400 its reverse (451181), we get a palindrome (18566581).

The spelling of 18115400 in words is "eighteen million, one hundred fifteen thousand, four hundred".