11719810561 has 4 divisors (see below), whose sum is σ = 11763378900. Its totient is φ = 11676242224.

The previous prime is 11719810549. The next prime is 11719810567. The reversal of 11719810561 is 16501891711.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16501891711 = 1303 ⋅12664537.

It can be written as a sum of positive squares in 2 ways, for example, as 3926275600 + 7793534961 = 62660^2 + 88281^2 .

It is a cyclic number.

It is not a de Polignac number, because 11719810561 - 2¹⁹ = 11719286273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11719810567) 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, 21783766 + ... + 21784303.

It is an arithmetic number, because the mean of its divisors is an integer number (2940844725).

Almost surely, 2^11719810561 is an apocalyptic number.

It is an amenable number.

11719810561 is a deficient number, since it is larger than the sum of its proper divisors (43568339).

11719810561 is an equidigital number, since it uses as much as digits as its factorization.

11719810561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43568338.

The product of its (nonzero) digits is 15120, while the sum is 40.

The spelling of 11719810561 in words is "eleven billion, seven hundred nineteen million, eight hundred ten thousand, five hundred sixty-one".