21222212201 has 2 divisors, whose sum is σ = 21222212202. Its totient is φ = 21222212200.

The previous prime is 21222212197. The next prime is 21222212237. The reversal of 21222212201 is 10221222212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20706922201 + 515290000 = 143899^2 + 22700^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222212201 - 2² = 21222212197 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21222212201.

It is not a weakly prime, because it can be changed into another prime (21222218201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611106100 + 10611106101.

It is an arithmetic number, because the mean of its divisors is an integer number (10611106101).

Almost surely, 2^21222212201 is an apocalyptic number.

It is an amenable number.

21222212201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222212201 is an equidigital number, since it uses as much as digits as its factorization.

21222212201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21222212201 its reverse (10221222212), we get a palindrome (31443434413).

It can be divided in two parts, 21 and 222212201, that added together give a palindrome (222212222).

The spelling of 21222212201 in words is "twenty-one billion, two hundred twenty-two million, two hundred twelve thousand, two hundred one".