18725666 has 4 divisors (see below), whose sum is σ = 28088502. Its totient is φ = 9362832.

The previous prime is 18725647. The next prime is 18725669. The reversal of 18725666 is 66652781.

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., 17048641 + 1677025 = 4129^2 + 1295^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18725669) by changing a digit.

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, 4681415 + ... + 4681418.

Almost surely, 2^18725666 is an apocalyptic number.

18725666 is a deficient number, since it is larger than the sum of its proper divisors (9362836).

18725666 is an equidigital number, since it uses as much as digits as its factorization.

18725666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9362835.

The product of its digits is 120960, while the sum is 41.

The square root of 18725666 is about 4327.3162583754. The cubic root of 18725666 is about 265.5496648365.

It can be divided in two parts, 18725 and 666, that added together give a palindrome (19391).

The spelling of 18725666 in words is "eighteen million, seven hundred twenty-five thousand, six hundred sixty-six".