9913991509 has 4 divisors (see below), whose sum is σ = 9915053260. Its totient is φ = 9912929760.

The previous prime is 9913991471. The next prime is 9913991537. The reversal of 9913991509 is 9051993199.

9913991509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9051993199 = 127 ⋅71275537.

It can be written as a sum of positive squares in 2 ways, for example, as 4533328900 + 5380662609 = 67330^2 + 73353^2 .

It is a cyclic number.

It is not a de Polignac number, because 9913991509 - 2²⁷ = 9779773781 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 9913991509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9913991909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 516744 + ... + 535585.

It is an arithmetic number, because the mean of its divisors is an integer number (2478763315).

Almost surely, 2^9913991509 is an apocalyptic number.

It is an amenable number.

9913991509 is a deficient number, since it is larger than the sum of its proper divisors (1061751).

9913991509 is a wasteful number, since it uses less digits than its factorization.

9913991509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1061750.

The product of its (nonzero) digits is 885735, while the sum is 55.

The square root of 9913991509 is about 99569.0288644014. The cubic root of 9913991509 is about 2148.2402408796.

The spelling of 9913991509 in words is "nine billion, nine hundred thirteen million, nine hundred ninety-one thousand, five hundred nine".