18943218 has 24 divisors (see below), whose sum is σ = 46907328. Its totient is φ = 5412312.

The previous prime is 18943217. The next prime is 18943229. The reversal of 18943218 is 81234981.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (18943217) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 75046 + ... + 75297.

It is an arithmetic number, because the mean of its divisors is an integer number (1954472).

Almost surely, 2^18943218 is an apocalyptic number.

18943218 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18943218 is an abundant number, since it is smaller than the sum of its proper divisors (27964110).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18943218 is a wasteful number, since it uses less digits than its factorization.

18943218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150358 (or 150355 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 18943218 is about 4352.3807278316. The cubic root of 18943218 is about 266.5740800104.

The spelling of 18943218 in words is "eighteen million, nine hundred forty-three thousand, two hundred eighteen".