18719729 has 4 divisors (see below), whose sum is σ = 21393984. Its totient is φ = 16045476.

The previous prime is 18719713. The next prime is 18719747. The reversal of 18719729 is 92791781.

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: 92791781 = 4751 ⋅19531.

It is a cyclic number.

It is not a de Polignac number, because 18719729 - 2⁴ = 18719713 is a prime.

It is a Duffinian number.

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 18719729.

It is not an unprimeable number, because it can be changed into a prime (18719429) 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, 1337117 + ... + 1337130.

It is an arithmetic number, because the mean of its divisors is an integer number (5348496).

Almost surely, 2^18719729 is an apocalyptic number.

It is an amenable number.

18719729 is a deficient number, since it is larger than the sum of its proper divisors (2674255).

18719729 is an equidigital number, since it uses as much as digits as its factorization.

18719729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2674254.

The product of its digits is 63504, while the sum is 44.

The square root of 18719729 is about 4326.6302129949. The cubic root of 18719729 is about 265.5215975659.

The spelling of 18719729 in words is "eighteen million, seven hundred nineteen thousand, seven hundred twenty-nine".