221166565679 has 2 divisors, whose sum is σ = 221166565680. Its totient is φ = 221166565678.

The previous prime is 221166565619. The next prime is 221166565687. The reversal of 221166565679 is 976565661122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221166565679 - 2⁸ = 221166565423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221166565619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110583282839 + 110583282840.

It is an arithmetic number, because the mean of its divisors is an integer number (110583282840).

Almost surely, 2^221166565679 is an apocalyptic number.

221166565679 is a deficient number, since it is larger than the sum of its proper divisors (1).

221166565679 is an equidigital number, since it uses as much as digits as its factorization.

221166565679 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8164800, while the sum is 56.

The spelling of 221166565679 in words is "two hundred twenty-one billion, one hundred sixty-six million, five hundred sixty-five thousand, six hundred seventy-nine".