21220312189 has 2 divisors, whose sum is σ = 21220312190. Its totient is φ = 21220312188.

The previous prime is 21220312181. The next prime is 21220312229. The reversal of 21220312189 is 98121302212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15667528900 + 5552783289 = 125170^2 + 74517^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220312189 - 2³ = 21220312181 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21220312189.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21220312181) 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, 10610156094 + 10610156095.

It is an arithmetic number, because the mean of its divisors is an integer number (10610156095).

Almost surely, 2^21220312189 is an apocalyptic number.

It is an amenable number.

21220312189 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220312189 is an equidigital number, since it uses as much as digits as its factorization.

21220312189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 31.

The spelling of 21220312189 in words is "twenty-one billion, two hundred twenty million, three hundred twelve thousand, one hundred eighty-nine".