221065261805 has 18 divisors (see below), whose sum is σ = 266577790734. Its totient is φ = 175990106544.

The previous prime is 221065261799. The next prime is 221065261811. The reversal of 221065261805 is 508162560122.

221065261805 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (221065261799) and next prime (221065261811).

It can be written as a sum of positive squares in only one way, i.e., 176852209444 + 44213052361 = 420538^2 + 210269^2 .

It is not a de Polignac number, because 221065261805 - 2²⁶ = 220998152941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 297530264 + ... + 297531006.

It is an arithmetic number, because the mean of its divisors is an integer number (14809877263).

Almost surely, 2^221065261805 is an apocalyptic number.

It is an amenable number.

221065261805 is a deficient number, since it is larger than the sum of its proper divisors (45512528929).

221065261805 is an frugal number, since it uses more digits than its factorization.

221065261805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2057 (or 1031 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 38.

The spelling of 221065261805 in words is "two hundred twenty-one billion, sixty-five million, two hundred sixty-one thousand, eight hundred five".