221064819791 has 2 divisors, whose sum is σ = 221064819792. Its totient is φ = 221064819790.

The previous prime is 221064819761. The next prime is 221064819799. The reversal of 221064819791 is 197918460122.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221064819791 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221064819799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110532409895 + 110532409896.

It is an arithmetic number, because the mean of its divisors is an integer number (110532409896).

Almost surely, 2^221064819791 is an apocalyptic number.

221064819791 is a deficient number, since it is larger than the sum of its proper divisors (1).

221064819791 is an equidigital number, since it uses as much as digits as its factorization.

221064819791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 50.

The spelling of 221064819791 in words is "two hundred twenty-one billion, sixty-four million, eight hundred nineteen thousand, seven hundred ninety-one".