11991173120 has 96 divisors (see below), whose sum is σ = 29550339000. Its totient is φ = 4666687488.

The previous prime is 11991173081. The next prime is 11991173179. The reversal of 11991173120 is 2137119911.

It can be written as a sum of positive squares in 4 ways, for example, as 11984118784 + 7054336 = 109472^2 + 2656^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 363056 + ... + 394704.

Almost surely, 2^11991173120 is an apocalyptic number.

11991173120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 11991173120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14775169500).

11991173120 is an abundant number, since it is smaller than the sum of its proper divisors (17559165880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11991173120 is an equidigital number, since it uses as much as digits as its factorization.

11991173120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31713 (or 31693 counting only the distinct ones).

The product of its (nonzero) digits is 3402, while the sum is 35.

The spelling of 11991173120 in words is "eleven billion, nine hundred ninety-one million, one hundred seventy-three thousand, one hundred twenty".