17985934517 has 4 divisors (see below), whose sum is σ = 18055918956. Its totient is φ = 17915950080.

The previous prime is 17985934511. The next prime is 17985934553. The reversal of 17985934517 is 71543958971.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71543958971 = 47 ⋅1522211893.

It can be written as a sum of positive squares in 2 ways, for example, as 10924221361 + 7061713156 = 104519^2 + 84034^2 .

It is a cyclic number.

It is not a de Polignac number, because 17985934517 - 2⁶ = 17985934453 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 (17985934511) 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, 34991834 + ... + 34992347.

It is an arithmetic number, because the mean of its divisors is an integer number (4513979739).

Almost surely, 2^17985934517 is an apocalyptic number.

It is an amenable number.

17985934517 is a deficient number, since it is larger than the sum of its proper divisors (69984439).

17985934517 is an equidigital number, since it uses as much as digits as its factorization.

17985934517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69984438.

The product of its digits is 9525600, while the sum is 59.

The spelling of 17985934517 in words is "seventeen billion, nine hundred eighty-five million, nine hundred thirty-four thousand, five hundred seventeen".