21220108904849 has 2 divisors, whose sum is σ = 21220108904850. Its totient is φ = 21220108904848.

The previous prime is 21220108904837. The next prime is 21220108904851. The reversal of 21220108904849 is 94840980102212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19432165525249 + 1787943379600 = 4408193^2 + 1337140^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220108904849 - 2¹⁶ = 21220108839313 is a prime.

It is a super-2 number, since 2×21220108904849² (a number of 27 digits) contains 22 as substring.

Together with 21220108904851, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21220108904797 and 21220108904806.

It is not a weakly prime, because it can be changed into another prime (21220108900849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610054452424 + 10610054452425.

It is an arithmetic number, because the mean of its divisors is an integer number (10610054452425).

Almost surely, 2^{21220108904849} is an apocalyptic number.

It is an amenable number.

21220108904849 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220108904849 is an equidigital number, since it uses as much as digits as its factorization.

21220108904849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 663552, while the sum is 50.

The spelling of 21220108904849 in words is "twenty-one trillion, two hundred twenty billion, one hundred eight million, nine hundred four thousand, eight hundred forty-nine".