21120001022221 has 2 divisors, whose sum is σ = 21120001022222. Its totient is φ = 21120001022220.

The previous prime is 21120001022213. The next prime is 21120001022233. The reversal of 21120001022221 is 12222010002112.

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., 20538616122025 + 581384900196 = 4531955^2 + 762486^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120001022221 - 2³ = 21120001022213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120001022195 and 21120001022204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120001022521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560000511110 + 10560000511111.

It is an arithmetic number, because the mean of its divisors is an integer number (10560000511111).

Almost surely, 2^{21120001022221} is an apocalyptic number.

It is an amenable number.

21120001022221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120001022221 is an equidigital number, since it uses as much as digits as its factorization.

21120001022221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21120001022221 its reverse (12222010002112), we get a palindrome (33342011024333).

The spelling of 21120001022221 in words is "twenty-one trillion, one hundred twenty billion, one million, twenty-two thousand, two hundred twenty-one".