18665506 has 4 divisors (see below), whose sum is σ = 27998262. Its totient is φ = 9332752.

The previous prime is 18665461. The next prime is 18665509. The reversal of 18665506 is 60556681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13024881 + 5640625 = 3609^2 + 2375^2 .

It is a super-2 number, since 2×18665506² = 696802228472072, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18665509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4666375 + ... + 4666378.

Almost surely, 2^18665506 is an apocalyptic number.

18665506 is a deficient number, since it is larger than the sum of its proper divisors (9332756).

18665506 is an equidigital number, since it uses as much as digits as its factorization.

18665506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9332755.

The product of its (nonzero) digits is 43200, while the sum is 37.

The square root of 18665506 is about 4320.3594757844. The cubic root of 18665506 is about 265.2649823660.

The spelling of 18665506 in words is "eighteen million, six hundred sixty-five thousand, five hundred six".