18686645 has 12 divisors (see below), whose sum is σ = 23176620. Its totient is φ = 14463360.

The previous prime is 18686641. The next prime is 18686651. The reversal of 18686645 is 54668681.

It can be written as a sum of positive squares in 2 ways, for example, as 10195249 + 8491396 = 3193^2 + 2914^2 .

It is not a de Polignac number, because 18686645 - 2² = 18686641 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18686596 and 18686605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18686641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2861 + ... + 6749.

It is an arithmetic number, because the mean of its divisors is an integer number (1931385).

Almost surely, 2^18686645 is an apocalyptic number.

It is an amenable number.

18686645 is a deficient number, since it is larger than the sum of its proper divisors (4489975).

18686645 is an equidigital number, since it uses as much as digits as its factorization.

18686645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3956 (or 3925 counting only the distinct ones).

The product of its digits is 276480, while the sum is 44.

The square root of 18686645 is about 4322.8052234631. The cubic root of 18686645 is about 265.3650836072.

The spelling of 18686645 in words is "eighteen million, six hundred eighty-six thousand, six hundred forty-five".