18686945 has 8 divisors (see below), whose sum is σ = 22449960. Its totient is φ = 14932480.

The previous prime is 18686911. The next prime is 18686947. The reversal of 18686945 is 54968681.

It can be written as a sum of positive squares in 4 ways, for example, as 12845056 + 5841889 = 3584^2 + 2417^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18686945 - 2¹² = 18682849 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 18686945.

It is not an unprimeable number, because it can be changed into a prime (18686947) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4625 + ... + 7665.

It is an arithmetic number, because the mean of its divisors is an integer number (2806245).

Almost surely, 2^18686945 is an apocalyptic number.

It is an amenable number.

18686945 is a deficient number, since it is larger than the sum of its proper divisors (3763015).

18686945 is a wasteful number, since it uses less digits than its factorization.

18686945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4275.

The product of its digits is 414720, while the sum is 47.

The square root of 18686945 is about 4322.8399230136. The cubic root of 18686945 is about 265.3665036784.

The spelling of 18686945 in words is "eighteen million, six hundred eighty-six thousand, nine hundred forty-five".