221805208111679 has 4 divisors (see below), whose sum is σ = 226524467858784. Its totient is φ = 217085948364576.

The previous prime is 221805208111651. The next prime is 221805208111783. The reversal of 221805208111679 is 976111802508122.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221805208111679 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221805208111679.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221805208111609) 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, 2359629873482 + ... + 2359629873575.

It is an arithmetic number, because the mean of its divisors is an integer number (56631116964696).

Almost surely, 2^{221805208111679} is an apocalyptic number.

221805208111679 is a deficient number, since it is larger than the sum of its proper divisors (4719259747105).

221805208111679 is an equidigital number, since it uses as much as digits as its factorization.

221805208111679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4719259747104.

The product of its (nonzero) digits is 967680, while the sum is 53.

The spelling of 221805208111679 in words is "two hundred twenty-one trillion, eight hundred five billion, two hundred eight million, one hundred eleven thousand, six hundred seventy-nine".