21112002221 has 2 divisors, whose sum is σ = 21112002222. Its totient is φ = 21112002220.

The previous prime is 21112002193. The next prime is 21112002253. The reversal of 21112002221 is 12220021112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20980074025 + 131928196 = 144845^2 + 11486^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112002221 - 2²⁶ = 21044893357 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21112002196 and 21112002205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112005221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556001110 + 10556001111.

It is an arithmetic number, because the mean of its divisors is an integer number (10556001111).

Almost surely, 2^21112002221 is an apocalyptic number.

It is an amenable number.

21112002221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112002221 is an equidigital number, since it uses as much as digits as its factorization.

21112002221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21112002221 its reverse (12220021112), we get a palindrome (33332023333).

The spelling of 21112002221 in words is "twenty-one billion, one hundred twelve million, two thousand, two hundred twenty-one".