18018947 has 4 divisors (see below), whose sum is σ = 18640320. Its totient is φ = 17397576.

The previous prime is 18018943. The next prime is 18018953. The reversal of 18018947 is 74981081.

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

It is a cyclic number.

It is not a de Polignac number, because 18018947 - 2² = 18018943 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18018947.

It is not an unprimeable number, because it can be changed into a prime (18018941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 310643 + ... + 310700.

It is an arithmetic number, because the mean of its divisors is an integer number (4660080).

Almost surely, 2^18018947 is an apocalyptic number.

18018947 is a deficient number, since it is larger than the sum of its proper divisors (621373).

18018947 is an equidigital number, since it uses as much as digits as its factorization.

18018947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 621372.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 18018947 is about 4244.8730251917. The cubic root of 18018947 is about 262.1660612262.

The spelling of 18018947 in words is "eighteen million, eighteen thousand, nine hundred forty-seven".