18942218 has 4 divisors (see below), whose sum is σ = 28413330. Its totient is φ = 9471108.

The previous prime is 18942211. The next prime is 18942223. The reversal of 18942218 is 81224981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81224981 = 19 ⋅4274999.

It can be written as a sum of positive squares in only one way, i.e., 18515809 + 426409 = 4303^2 + 653^2 .

It is not an unprimeable number, because it can be changed into a prime (18942211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4735553 + ... + 4735556.

Almost surely, 2^18942218 is an apocalyptic number.

18942218 is a deficient number, since it is larger than the sum of its proper divisors (9471112).

18942218 is an equidigital number, since it uses as much as digits as its factorization.

18942218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9471111.

The product of its digits is 9216, while the sum is 35.

The square root of 18942218 is about 4352.2658466596. The cubic root of 18942218 is about 266.5693891712.

The spelling of 18942218 in words is "eighteen million, nine hundred forty-two thousand, two hundred eighteen".