18718673 has 4 divisors (see below), whose sum is σ = 19175268. Its totient is φ = 18262080.

The previous prime is 18718669. The next prime is 18718681. The reversal of 18718673 is 37681781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37681781 = 53 ⋅710977.

It can be written as a sum of positive squares in 2 ways, for example, as 8427409 + 10291264 = 2903^2 + 3208^2 .

It is a cyclic number.

It is not a de Polignac number, because 18718673 - 2² = 18718669 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 456553 = 18718673 / (1 + 8 + 7 + 1 + 8 + 6 + 7 + 3).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18718673.

It is not an unprimeable number, because it can be changed into a prime (18718603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 228236 + ... + 228317.

It is an arithmetic number, because the mean of its divisors is an integer number (4793817).

Almost surely, 2^18718673 is an apocalyptic number.

It is an amenable number.

18718673 is a deficient number, since it is larger than the sum of its proper divisors (456595).

18718673 is an equidigital number, since it uses as much as digits as its factorization.

18718673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456594.

The product of its digits is 56448, while the sum is 41.

The square root of 18718673 is about 4326.5081763473. The cubic root of 18718673 is about 265.5166046859.

It can be divided in two parts, 18718 and 673, that added together give a palindrome (19391).

The spelling of 18718673 in words is "eighteen million, seven hundred eighteen thousand, six hundred seventy-three".