18328978 has 4 divisors (see below), whose sum is σ = 27493470. Its totient is φ = 9164488.

The previous prime is 18328969. The next prime is 18328979. The reversal of 18328978 is 87982381.

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

It can be written as a sum of positive squares in only one way, i.e., 12341169 + 5987809 = 3513^2 + 2447^2 .

It is not an unprimeable number, because it can be changed into a prime (18328979) 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 as a sum of consecutive naturals, namely, 4582243 + ... + 4582246.

Almost surely, 2^18328978 is an apocalyptic number.

18328978 is a deficient number, since it is larger than the sum of its proper divisors (9164492).

18328978 is an equidigital number, since it uses as much as digits as its factorization.

18328978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9164491.

The product of its digits is 193536, while the sum is 46.

The square root of 18328978 is about 4281.2355693187. The cubic root of 18328978 is about 263.6611143772.

It can be divided in two parts, 18328 and 978, that added together give a triangular number (19306 = T₁₉₆).

The spelling of 18328978 in words is "eighteen million, three hundred twenty-eight thousand, nine hundred seventy-eight".