221221622173 has 2 divisors, whose sum is σ = 221221622174. Its totient is φ = 221221622172.

The previous prime is 221221622159. The next prime is 221221622189. The reversal of 221221622173 is 371226122122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 202012493764 + 19209128409 = 449458^2 + 138597^2 .

It is a cyclic number.

It is not a de Polignac number, because 221221622173 - 2³⁷ = 83782668701 is a prime.

It is a super-2 number, since 2×221221622173² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221221622123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610811086 + 110610811087.

It is an arithmetic number, because the mean of its divisors is an integer number (110610811087).

Almost surely, 2^221221622173 is an apocalyptic number.

It is an amenable number.

221221622173 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221622173 is an equidigital number, since it uses as much as digits as its factorization.

221221622173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 31.

Adding to 221221622173 its reverse (371226122122), we get a palindrome (592447744295).

The spelling of 221221622173 in words is "two hundred twenty-one billion, two hundred twenty-one million, six hundred twenty-two thousand, one hundred seventy-three".