18613728 has 108 divisors (see below), whose sum is σ = 61621560. Its totient is φ = 5314176.

The previous prime is 18613709. The next prime is 18613729. The reversal of 18613728 is 82731681.

18613728 is a `hidden beast` number, since 18 + 613 + 7 + 28 = 666.

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

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

It is a junction number, because it is equal to n+sod(n) for n = 18613692 and 18613701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18613729) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 13453 + ... + 14771.

It is an arithmetic number, because the mean of its divisors is an integer number (570570).

Almost surely, 2^18613728 is an apocalyptic number.

18613728 is a gapful number since it is divisible by the number (18) 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 18613728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30810780).

18613728 is an abundant number, since it is smaller than the sum of its proper divisors (43007832).

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

18613728 is a wasteful number, since it uses less digits than its factorization.

18613728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1349 (or 1331 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 18613728 is about 4314.3629889011. The cubic root of 18613728 is about 265.0194740643.

The spelling of 18613728 in words is "eighteen million, six hundred thirteen thousand, seven hundred twenty-eight".