21220211689 has 2 divisors, whose sum is σ = 21220211690. Its totient is φ = 21220211688.

The previous prime is 21220211671. The next prime is 21220211713. The reversal of 21220211689 is 98611202212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18061209664 + 3159002025 = 134392^2 + 56205^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220211689 - 2¹³ = 21220203497 is a prime.

It is not a weakly prime, because it can be changed into another prime (21220211629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610105844 + 10610105845.

It is an arithmetic number, because the mean of its divisors is an integer number (10610105845).

Almost surely, 2^21220211689 is an apocalyptic number.

It is an amenable number.

21220211689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220211689 is an equidigital number, since it uses as much as digits as its factorization.

21220211689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 34.

The spelling of 21220211689 in words is "twenty-one billion, two hundred twenty million, two hundred eleven thousand, six hundred eighty-nine".