18728329 has 4 divisors (see below), whose sum is σ = 18913860. Its totient is φ = 18542800.

The previous prime is 18728323. The next prime is 18728363. The reversal of 18728329 is 92382781.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18292729 + 435600 = 4277^2 + 660^2 .

It is a cyclic number.

It is not a de Polignac number, because 18728329 - 2³ = 18728321 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18728291 and 18728300.

It is not an unprimeable number, because it can be changed into a prime (18728321) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92614 + ... + 92815.

It is an arithmetic number, because the mean of its divisors is an integer number (4728465).

Almost surely, 2^18728329 is an apocalyptic number.

It is an amenable number.

18728329 is a deficient number, since it is larger than the sum of its proper divisors (185531).

18728329 is a wasteful number, since it uses less digits than its factorization.

18728329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185530.

The product of its digits is 48384, while the sum is 40.

The square root of 18728329 is about 4327.6239439212. The cubic root of 18728329 is about 265.5622522881.

It can be divided in two parts, 1872 and 8329, that added together give a palindrome (10201).

The spelling of 18728329 in words is "eighteen million, seven hundred twenty-eight thousand, three hundred twenty-nine".