11566781249 has 4 divisors (see below), whose sum is σ = 12247180164. Its totient is φ = 10886382336.

The previous prime is 11566781203. The next prime is 11566781269. The reversal of 11566781249 is 94218766511.

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 7111886224 + 4454895025 = 84332^2 + 66745^2 .

It is a cyclic number.

It is not a de Polignac number, because 11566781249 - 2³² = 7271813953 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11566781197 and 11566781206.

It is not an unprimeable number, because it can be changed into a prime (11566781269) 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, 340199432 + ... + 340199465.

It is an arithmetic number, because the mean of its divisors is an integer number (3061795041).

Almost surely, 2^11566781249 is an apocalyptic number.

It is an amenable number.

11566781249 is a deficient number, since it is larger than the sum of its proper divisors (680398915).

11566781249 is an equidigital number, since it uses as much as digits as its factorization.

11566781249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680398914.

The product of its digits is 725760, while the sum is 50.

The spelling of 11566781249 in words is "eleven billion, five hundred sixty-six million, seven hundred eighty-one thousand, two hundred forty-nine".