221688720191 has 2 divisors, whose sum is σ = 221688720192. Its totient is φ = 221688720190.

The previous prime is 221688720151. The next prime is 221688720247. The reversal of 221688720191 is 191027886122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221688720191 - 2¹⁰ = 221688719167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221688720151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110844360095 + 110844360096.

It is an arithmetic number, because the mean of its divisors is an integer number (110844360096).

Almost surely, 2^221688720191 is an apocalyptic number.

221688720191 is a deficient number, since it is larger than the sum of its proper divisors (1).

221688720191 is an equidigital number, since it uses as much as digits as its factorization.

221688720191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 193536, while the sum is 47.

The spelling of 221688720191 in words is "two hundred twenty-one billion, six hundred eighty-eight million, seven hundred twenty thousand, one hundred ninety-one".