11580121891 has 4 divisors (see below), whose sum is σ = 12470900512. Its totient is φ = 10689343272.

The previous prime is 11580121873. The next prime is 11580121909. The reversal of 11580121891 is 19812108511.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (11580121873) and next prime (11580121909).

It is a cyclic number.

It is not a de Polignac number, because 11580121891 - 2⁹ = 11580121379 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 11580121891.

It is not an unprimeable number, because it can be changed into a prime (11580125891) 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, 445389291 + ... + 445389316.

It is an arithmetic number, because the mean of its divisors is an integer number (3117725128).

Almost surely, 2^11580121891 is an apocalyptic number.

11580121891 is a deficient number, since it is larger than the sum of its proper divisors (890778621).

11580121891 is an equidigital number, since it uses as much as digits as its factorization.

11580121891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 890778620.

The product of its (nonzero) digits is 5760, while the sum is 37.

The spelling of 11580121891 in words is "eleven billion, five hundred eighty million, one hundred twenty-one thousand, eight hundred ninety-one".