17991060749 has 4 divisors (see below), whose sum is σ = 18068275836. Its totient is φ = 17913845664.

The previous prime is 17991060743. The next prime is 17991060797. The reversal of 17991060749 is 94706019971.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94706019971 = 2833 ⋅33429587.

It can be written as a sum of positive squares in 2 ways, for example, as 8694630025 + 9296430724 = 93245^2 + 96418^2 .

It is a cyclic number.

It is not a de Polignac number, because 17991060749 - 2⁴ = 17991060733 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 17991060749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (17991060743) 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, 38607194 + ... + 38607659.

It is an arithmetic number, because the mean of its divisors is an integer number (4517068959).

Almost surely, 2^17991060749 is an apocalyptic number.

It is an amenable number.

17991060749 is a deficient number, since it is larger than the sum of its proper divisors (77215087).

17991060749 is an equidigital number, since it uses as much as digits as its factorization.

17991060749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77215086.

The product of its (nonzero) digits is 857304, while the sum is 53.

The spelling of 17991060749 in words is "seventeen billion, nine hundred ninety-one million, sixty thousand, seven hundred forty-nine".