11556671261 has 4 divisors (see below), whose sum is σ = 11576700732. Its totient is φ = 11536641792.

The previous prime is 11556671237. The next prime is 11556671267. The reversal of 11556671261 is 16217665511.

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 10301032036 + 1255639225 = 101494^2 + 35435^2 .

It is a cyclic number.

It is not a de Polignac number, because 11556671261 - 2²⁶ = 11489562397 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 (11556671267) 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, 10013870 + ... + 10015023.

It is an arithmetic number, because the mean of its divisors is an integer number (2894175183).

Almost surely, 2^11556671261 is an apocalyptic number.

It is an amenable number.

11556671261 is a deficient number, since it is larger than the sum of its proper divisors (20029471).

11556671261 is an equidigital number, since it uses as much as digits as its factorization.

11556671261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20029470.

The product of its digits is 75600, while the sum is 41.

The spelling of 11556671261 in words is "eleven billion, five hundred fifty-six million, six hundred seventy-one thousand, two hundred sixty-one".