18943689 has 4 divisors (see below), whose sum is σ = 25258256. Its totient is φ = 12629124.

The previous prime is 18943669. The next prime is 18943747. The reversal of 18943689 is 98634981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 98634981 = 3 ⋅32878327.

It is not a de Polignac number, because 18943689 - 2¹² = 18939593 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18943609) 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, 3157279 + ... + 3157284.

It is an arithmetic number, because the mean of its divisors is an integer number (6314564).

Almost surely, 2^18943689 is an apocalyptic number.

It is an amenable number.

18943689 is a deficient number, since it is larger than the sum of its proper divisors (6314567).

18943689 is an equidigital number, since it uses as much as digits as its factorization.

18943689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6314566.

The product of its digits is 373248, while the sum is 48.

The square root of 18943689 is about 4352.4348358132. The cubic root of 18943689 is about 266.5762893385.

The spelling of 18943689 in words is "eighteen million, nine hundred forty-three thousand, six hundred eighty-nine".