221000111221 has 2 divisors, whose sum is σ = 221000111222. Its totient is φ = 221000111220.

The previous prime is 221000111083. The next prime is 221000111273. The reversal of 221000111221 is 122111000122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 216118992996 + 4881118225 = 464886^2 + 69865^2 .

It is a cyclic number.

It is not a de Polignac number, because 221000111221 - 2¹¹ = 221000109173 is a prime.

It is a super-2 number, since 2×221000111221² (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 (221000111621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110500055610 + 110500055611.

It is an arithmetic number, because the mean of its divisors is an integer number (110500055611).

Almost surely, 2^221000111221 is an apocalyptic number.

It is an amenable number.

221000111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221000111221 is an equidigital number, since it uses as much as digits as its factorization.

221000111221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 221000111221 its reverse (122111000122), we get a palindrome (343111111343).

It can be divided in two parts, 2210001 and 11221, that added together give a palindrome (2221222).

The spelling of 221000111221 in words is "two hundred twenty-one billion, one hundred eleven thousand, two hundred twenty-one".