18118728 has 40 divisors (see below), whose sum is σ = 50751030. Its totient is φ = 6039360.

The previous prime is 18118721. The next prime is 18118777. The reversal of 18118728 is 82781181.

It can be written as a sum of positive squares in only one way, i.e., 16990884 + 1127844 = 4122^2 + 1062^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18118692 and 18118701.

It is not an unprimeable number, because it can be changed into a prime (18118721) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 13333 + ... + 14628.

Almost surely, 2^18118728 is an apocalyptic number.

18118728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

18118728 is an abundant number, since it is smaller than the sum of its proper divisors (32632302).

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

18118728 is a wasteful number, since it uses less digits than its factorization.

18118728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27979 (or 27966 counting only the distinct ones).

The product of its digits is 7168, while the sum is 36.

The square root of 18118728 is about 4256.6099187029. The cubic root of 18118728 is about 262.6490908158.

The spelling of 18118728 in words is "eighteen million, one hundred eighteen thousand, seven hundred twenty-eight".