18309785717 has 4 divisors (see below), whose sum is σ = 18310208460. Its totient is φ = 18309362976.

The previous prime is 18309785677. The next prime is 18309785749. The reversal of 18309785717 is 71758790381.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2395710916 + 15914074801 = 48946^2 + 126151^2 .

It is a cyclic number.

It is not a de Polignac number, because 18309785717 - 2⁶ = 18309785653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18309785777) 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, 137888 + ... + 235865.

It is an arithmetic number, because the mean of its divisors is an integer number (4577552115).

Almost surely, 2^18309785717 is an apocalyptic number.

It is an amenable number.

18309785717 is a deficient number, since it is larger than the sum of its proper divisors (422743).

18309785717 is an equidigital number, since it uses as much as digits as its factorization.

18309785717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422742.

The product of its (nonzero) digits is 2963520, while the sum is 56.

The spelling of 18309785717 in words is "eighteen billion, three hundred nine million, seven hundred eighty-five thousand, seven hundred seventeen".