21211222103809 has 2 divisors, whose sum is σ = 21211222103810. Its totient is φ = 21211222103808.

The previous prime is 21211222103807. The next prime is 21211222103867. The reversal of 21211222103809 is 90830122211212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18373439280625 + 2837782823184 = 4286425^2 + 1684572^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211222103809 - 2¹ = 21211222103807 is a prime.

Together with 21211222103807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21211222103801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605611051904 + 10605611051905.

It is an arithmetic number, because the mean of its divisors is an integer number (10605611051905).

Almost surely, 2^{21211222103809} is an apocalyptic number.

It is an amenable number.

21211222103809 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211222103809 is an equidigital number, since it uses as much as digits as its factorization.

21211222103809 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 21211222103809 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-two million, one hundred three thousand, eight hundred nine".