11556836307821 has 4 divisors (see below), whose sum is σ = 13207812923232. Its totient is φ = 9905859692412.

The previous prime is 11556836307817. The next prime is 11556836307829. The reversal of 11556836307821 is 12870363865511.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 11556836307821 - 2² = 11556836307817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11556836307829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 825488307695 + ... + 825488307708.

It is an arithmetic number, because the mean of its divisors is an integer number (3301953230808).

Almost surely, 2^{11556836307821} is an apocalyptic number.

It is an amenable number.

11556836307821 is a deficient number, since it is larger than the sum of its proper divisors (1650976615411).

11556836307821 is an equidigital number, since it uses as much as digits as its factorization.

11556836307821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1650976615410.

The product of its (nonzero) digits is 7257600, while the sum is 56.

The spelling of 11556836307821 in words is "eleven trillion, five hundred fifty-six billion, eight hundred thirty-six million, three hundred seven thousand, eight hundred twenty-one".