211591085013818 has 4 divisors (see below), whose sum is σ = 317386627520730. Its totient is φ = 105795542506908.

The previous prime is 211591085013793. The next prime is 211591085013821. The reversal of 211591085013818 is 818310580195112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 167969194645849 + 43621890367969 = 12960293^2 + 6604687^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 211591085013818.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52897771253453 + ... + 52897771253456.

Almost surely, 2^{211591085013818} is an apocalyptic number.

211591085013818 is a deficient number, since it is larger than the sum of its proper divisors (105795542506912).

211591085013818 is a wasteful number, since it uses less digits than its factorization.

211591085013818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105795542506911.

The product of its (nonzero) digits is 691200, while the sum is 53.

The spelling of 211591085013818 in words is "two hundred eleven trillion, five hundred ninety-one billion, eighty-five million, thirteen thousand, eight hundred eighteen".