18328357 has 4 divisors (see below), whose sum is σ = 18823756. Its totient is φ = 17832960.

The previous prime is 18328333. The next prime is 18328367. The reversal of 18328357 is 75382381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75382381 = 409 ⋅184309.

It can be written as a sum of positive squares in 2 ways, for example, as 13549761 + 4778596 = 3681^2 + 2186^2 .

It is a cyclic number.

It is not a de Polignac number, because 18328357 - 2¹⁹ = 17804069 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 495361 = 18328357 / (1 + 8 + 3 + 2 + 8 + 3 + 5 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18328307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 247644 + ... + 247717.

It is an arithmetic number, because the mean of its divisors is an integer number (4705939).

Almost surely, 2^18328357 is an apocalyptic number.

It is an amenable number.

18328357 is a deficient number, since it is larger than the sum of its proper divisors (495399).

18328357 is an equidigital number, since it uses as much as digits as its factorization.

18328357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495398.

The product of its digits is 40320, while the sum is 37.

The square root of 18328357 is about 4281.1630429125. The cubic root of 18328357 is about 263.6581366625.

The spelling of 18328357 in words is "eighteen million, three hundred twenty-eight thousand, three hundred fifty-seven".