21001222189 has 2 divisors, whose sum is σ = 21001222190. Its totient is φ = 21001222188.

The previous prime is 21001222181. The next prime is 21001222219. The reversal of 21001222189 is 98122210012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13163661289 + 7837560900 = 114733^2 + 88530^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001222189 - 2³ = 21001222181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001222181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500611094 + 10500611095.

It is an arithmetic number, because the mean of its divisors is an integer number (10500611095).

Almost surely, 2^21001222189 is an apocalyptic number.

It is an amenable number.

21001222189 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001222189 is an equidigital number, since it uses as much as digits as its factorization.

21001222189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 28.

The spelling of 21001222189 in words is "twenty-one billion, one million, two hundred twenty-two thousand, one hundred eighty-nine".