18718728 has 64 divisors (see below), whose sum is σ = 54312960. Its totient is φ = 5265216.

The previous prime is 18718727. The next prime is 18718729. The reversal of 18718728 is 82781781.

It is an interprime number because it is at equal distance from previous prime (18718727) and next prime (18718729).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 18718728.

It is not an unprimeable number, because it can be changed into a prime (18718723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10425 + ... + 12087.

It is an arithmetic number, because the mean of its divisors is an integer number (848640).

Almost surely, 2^18718728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18718728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27156480).

18718728 is an abundant number, since it is smaller than the sum of its proper divisors (35594232).

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

18718728 is a wasteful number, since it uses less digits than its factorization.

18718728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1746 (or 1742 counting only the distinct ones).

The product of its digits is 50176, while the sum is 42.

The square root of 18718728 is about 4326.5145325077. The cubic root of 18718728 is about 265.5168647364.

It can be divided in two parts, 187 and 18728, that added together give a triangular number (18915 = T₁₉₄).

The spelling of 18718728 in words is "eighteen million, seven hundred eighteen thousand, seven hundred twenty-eight".