21222122121209 has 8 divisors (see below), whose sum is σ = 22479702840648. Its totient is φ = 19965565912320.

The previous prime is 21222122121197. The next prime is 21222122121223. The reversal of 21222122121209 is 90212122122212.

It can be written as a sum of positive squares in 4 ways, for example, as 8469031225600 + 12753090895609 = 2910160^2 + 3571147^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21222122121209 - 2²⁴ = 21222105343993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21222122121259) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 256084982 + ... + 256167839.

It is an arithmetic number, because the mean of its divisors is an integer number (2809962855081).

Almost surely, 2^{21222122121209} is an apocalyptic number.

It is an amenable number.

21222122121209 is a deficient number, since it is larger than the sum of its proper divisors (1257580719439).

21222122121209 is a wasteful number, since it uses less digits than its factorization.

21222122121209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 512255275.

The product of its (nonzero) digits is 2304, while the sum is 29.

The spelling of 21222122121209 in words is "twenty-one trillion, two hundred twenty-two billion, one hundred twenty-two million, one hundred twenty-one thousand, two hundred nine".