18509212 has 6 divisors (see below), whose sum is σ = 32391128. Its totient is φ = 9254604.

The previous prime is 18509207. The next prime is 18509261. The reversal of 18509212 is 21290581.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2313648 + ... + 2313655.

Almost surely, 2^18509212 is an apocalyptic number.

It is an amenable number.

18509212 is a deficient number, since it is larger than the sum of its proper divisors (13881916).

18509212 is a wasteful number, since it uses less digits than its factorization.

18509212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4627307 (or 4627305 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 18509212 is about 4302.2333734934. The cubic root of 18509212 is about 264.5225150365.

Adding to 18509212 its reverse (21290581), we get a palindrome (39799793).

It can be divided in two parts, 18509 and 212, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 18509212 in words is "eighteen million, five hundred nine thousand, two hundred twelve".