18243778 has 12 divisors (see below), whose sum is σ = 31833702. Its totient is φ = 7818720.

The previous prime is 18243773. The next prime is 18243793. The reversal of 18243778 is 87734281.

It can be written as a sum of positive squares in only one way, i.e., 9966649 + 8277129 = 3157^2 + 2877^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18243778.

It is not an unprimeable number, because it can be changed into a prime (18243773) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 92983 + ... + 93178.

Almost surely, 2^18243778 is an apocalyptic number.

18243778 is a deficient number, since it is larger than the sum of its proper divisors (13589924).

18243778 is a wasteful number, since it uses less digits than its factorization.

18243778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186177 (or 186170 counting only the distinct ones).

The product of its digits is 75264, while the sum is 40.

The square root of 18243778 is about 4271.2735805612. The cubic root of 18243778 is about 263.2519476459.

The spelling of 18243778 in words is "eighteen million, two hundred forty-three thousand, seven hundred seventy-eight".