18499221 has 12 divisors (see below), whose sum is σ = 28776748. Its totient is φ = 11384064.

The previous prime is 18499207. The next prime is 18499231. The reversal of 18499221 is 12299481.

It can be written as a sum of positive squares in 2 ways, for example, as 8820900 + 9678321 = 2970^2 + 3111^2 .

It is not a de Polignac number, because 18499221 - 2¹⁰ = 18498197 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18499231) 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 11 ways as a sum of consecutive naturals, for example, 78940 + ... + 79173.

Almost surely, 2^18499221 is an apocalyptic number.

It is an amenable number.

18499221 is a deficient number, since it is larger than the sum of its proper divisors (10277527).

18499221 is a wasteful number, since it uses less digits than its factorization.

18499221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158132 (or 158129 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 18499221 is about 4301.0720756574. The cubic root of 18499221 is about 264.4749113511.

The spelling of 18499221 in words is "eighteen million, four hundred ninety-nine thousand, two hundred twenty-one".