221151694991 has 2 divisors, whose sum is σ = 221151694992. Its totient is φ = 221151694990.

The previous prime is 221151694919. The next prime is 221151695033. The reversal of 221151694991 is 199496151122.

Together with previous prime (221151694919) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221151694991 - 2²⁶ = 221084586127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221151694901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110575847495 + 110575847496.

It is an arithmetic number, because the mean of its divisors is an integer number (110575847496).

Almost surely, 2^221151694991 is an apocalyptic number.

221151694991 is a deficient number, since it is larger than the sum of its proper divisors (1).

221151694991 is an equidigital number, since it uses as much as digits as its factorization.

221151694991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 349920, while the sum is 50.

The spelling of 221151694991 in words is "two hundred twenty-one billion, one hundred fifty-one million, six hundred ninety-four thousand, nine hundred ninety-one".