221237634217 has 2 divisors, whose sum is σ = 221237634218. Its totient is φ = 221237634216.

The previous prime is 221237634193. The next prime is 221237634227. The reversal of 221237634217 is 712436732122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 216467798121 + 4769836096 = 465261^2 + 69064^2 .

It is a cyclic number.

It is not a de Polignac number, because 221237634217 - 2¹⁵ = 221237601449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221237634217.

It is not a weakly prime, because it can be changed into another prime (221237634227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110618817108 + 110618817109.

It is an arithmetic number, because the mean of its divisors is an integer number (110618817109).

Almost surely, 2^221237634217 is an apocalyptic number.

It is an amenable number.

221237634217 is a deficient number, since it is larger than the sum of its proper divisors (1).

221237634217 is an equidigital number, since it uses as much as digits as its factorization.

221237634217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 40.

The spelling of 221237634217 in words is "two hundred twenty-one billion, two hundred thirty-seven million, six hundred thirty-four thousand, two hundred seventeen".