18117556 has 6 divisors (see below), whose sum is σ = 31705730. Its totient is φ = 9058776.

The previous prime is 18117523. The next prime is 18117559. The reversal of 18117556 is 65571181.

It can be written as a sum of positive squares in only one way, i.e., 11696400 + 6421156 = 3420^2 + 2534^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18117559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2264691 + ... + 2264698.

Almost surely, 2^18117556 is an apocalyptic number.

It is an amenable number.

18117556 is a deficient number, since it is larger than the sum of its proper divisors (13588174).

18117556 is a wasteful number, since it uses less digits than its factorization.

18117556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4529393 (or 4529391 counting only the distinct ones).

The product of its digits is 8400, while the sum is 34.

The square root of 18117556 is about 4256.4722482356. The cubic root of 18117556 is about 262.6434275895.

The spelling of 18117556 in words is "eighteen million, one hundred seventeen thousand, five hundred fifty-six".