18644986 has 4 divisors (see below), whose sum is σ = 27967482. Its totient is φ = 9322492.

The previous prime is 18644963. The next prime is 18644987. The reversal of 18644986 is 68944681.

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., 14584761 + 4060225 = 3819^2 + 2015^2 .

It is not an unprimeable number, because it can be changed into a prime (18644987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4661245 + ... + 4661248.

Almost surely, 2^18644986 is an apocalyptic number.

18644986 is a deficient number, since it is larger than the sum of its proper divisors (9322496).

18644986 is an equidigital number, since it uses as much as digits as its factorization.

18644986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9322495.

The product of its digits is 331776, while the sum is 46.

The square root of 18644986 is about 4317.9840203502. The cubic root of 18644986 is about 265.1677400099.

The spelling of 18644986 in words is "eighteen million, six hundred forty-four thousand, nine hundred eighty-six".