11817784085 has 4 divisors (see below), whose sum is σ = 14181340908. Its totient is φ = 9454227264.

The previous prime is 11817784007. The next prime is 11817784087. The reversal of 11817784085 is 58048771811.

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 1395620164 + 10422163921 = 37358^2 + 102089^2 .

It is a cyclic number.

It is not a de Polignac number, because 11817784085 - 2¹² = 11817779989 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11817784087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1181778404 + ... + 1181778413.

It is an arithmetic number, because the mean of its divisors is an integer number (3545335227).

Almost surely, 2^11817784085 is an apocalyptic number.

It is an amenable number.

11817784085 is a deficient number, since it is larger than the sum of its proper divisors (2363556823).

11817784085 is an equidigital number, since it uses as much as digits as its factorization.

11817784085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2363556822.

The product of its (nonzero) digits is 501760, while the sum is 50.

The spelling of 11817784085 in words is "eleven billion, eight hundred seventeen million, seven hundred eighty-four thousand, eighty-five".