18806218 has 4 divisors (see below), whose sum is σ = 28209330. Its totient is φ = 9403108.

The previous prime is 18806209. The next prime is 18806237. The reversal of 18806218 is 81260881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81260881 = 13 ⋅6250837.

It can be written as a sum of positive squares in only one way, i.e., 18774889 + 31329 = 4333^2 + 177^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4701553 + ... + 4701556.

Almost surely, 2^18806218 is an apocalyptic number.

18806218 is a deficient number, since it is larger than the sum of its proper divisors (9403112).

18806218 is an equidigital number, since it uses as much as digits as its factorization.

18806218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9403111.

The product of its (nonzero) digits is 6144, while the sum is 34.

The square root of 18806218 is about 4336.6136558379. The cubic root of 18806218 is about 265.9298908830.

The spelling of 18806218 in words is "eighteen million, eight hundred six thousand, two hundred eighteen".