21222221689 has 2 divisors, whose sum is σ = 21222221690. Its totient is φ = 21222221688.

The previous prime is 21222221641. The next prime is 21222221719. The reversal of 21222221689 is 98612222212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21221205625 + 1016064 = 145675^2 + 1008^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222221689 - 2¹⁵ = 21222188921 is a prime.

It is not a weakly prime, because it can be changed into another prime (21222221089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611110844 + 10611110845.

It is an arithmetic number, because the mean of its divisors is an integer number (10611110845).

Almost surely, 2^21222221689 is an apocalyptic number.

It is an amenable number.

21222221689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222221689 is an equidigital number, since it uses as much as digits as its factorization.

21222221689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 37.

The spelling of 21222221689 in words is "twenty-one billion, two hundred twenty-two million, two hundred twenty-one thousand, six hundred eighty-nine".