221968564779 has 16 divisors (see below), whose sum is σ = 335499046400. Its totient is φ = 129406774176.

The previous prime is 221968564771. The next prime is 221968564823. The reversal of 221968564779 is 977465869122.

It is a happy number.

It is not a de Polignac number, because 221968564779 - 2³ = 221968564771 is a prime.

It is a Smith number, since the sum of its digits (66) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221968564771) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 149775619 + ... + 149777100.

It is an arithmetic number, because the mean of its divisors is an integer number (20968690400).

Almost surely, 2^221968564779 is an apocalyptic number.

221968564779 is a deficient number, since it is larger than the sum of its proper divisors (113530481621).

221968564779 is a wasteful number, since it uses less digits than its factorization.

221968564779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299552754.

The product of its digits is 91445760, while the sum is 66.

The spelling of 221968564779 in words is "two hundred twenty-one billion, nine hundred sixty-eight million, five hundred sixty-four thousand, seven hundred seventy-nine".