13121220222221 has 16 divisors (see below), whose sum is σ = 13352568896304. Its totient is φ = 12892369910784.

The previous prime is 13121220222139. The next prime is 13121220222223. The reversal of 13121220222221 is 12222202212131.

It can be written as a sum of positive squares in 8 ways, for example, as 2886889837225 + 10234330384996 = 1699085^2 + 3199114^2 .

It is a cyclic number.

It is not a de Polignac number, because 13121220222221 - 2³⁸ = 12846342315277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13121220222223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5102351 + ... + 7230243.

It is an arithmetic number, because the mean of its divisors is an integer number (834535556019).

Almost surely, 2^{13121220222221} is an apocalyptic number.

It is an amenable number.

13121220222221 is a deficient number, since it is larger than the sum of its proper divisors (231348674083).

13121220222221 is a wasteful number, since it uses less digits than its factorization.

13121220222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2128480.

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 13121220222221 its reverse (12222202212131), we get a palindrome (25343422434352).

The spelling of 13121220222221 in words is "thirteen trillion, one hundred twenty-one billion, two hundred twenty million, two hundred twenty-two thousand, two hundred twenty-one".