11997517409 has 4 divisors (see below), whose sum is σ = 12223885716. Its totient is φ = 11771149104.

The previous prime is 11997517397. The next prime is 11997517447. The reversal of 11997517409 is 90471579911.

11997517409 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.

It can be written as a sum of positive squares in 2 ways, for example, as 5860361809 + 6137155600 = 76553^2 + 78340^2 .

It is a cyclic number.

It is not a de Polignac number, because 11997517409 - 2¹² = 11997513313 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53), and also a Moran number because the ratio is a prime number: 226368253 = 11997517409 / (1 + 1 + 9 + 9 + 7 + 5 + 1 + 7 + 4 + 0 + 9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11997517489) 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, 113184074 + ... + 113184179.

It is an arithmetic number, because the mean of its divisors is an integer number (3055971429).

Almost surely, 2^11997517409 is an apocalyptic number.

It is an amenable number.

11997517409 is a deficient number, since it is larger than the sum of its proper divisors (226368307).

11997517409 is an equidigital number, since it uses as much as digits as its factorization.

11997517409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226368306.

The product of its (nonzero) digits is 714420, while the sum is 53.

The spelling of 11997517409 in words is "eleven billion, nine hundred ninety-seven million, five hundred seventeen thousand, four hundred nine".