2121022221221 has 8 divisors (see below), whose sum is σ = 2245803563160. Its totient is φ = 1996242582528.

The previous prime is 2121022221217. The next prime is 2121022221271. The reversal of 2121022221221 is 1221222201212.

It can be written as a sum of positive squares in 4 ways, for example, as 363578850625 + 1757443370596 = 602975^2 + 1325686^2 .

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 2121022221221 - 2² = 2121022221217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121022221193 and 2121022221202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121022221271) 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, 2864495 + ... + 3528083.

It is an arithmetic number, because the mean of its divisors is an integer number (280725445395).

Almost surely, 2^{2121022221221} is an apocalyptic number.

It is an amenable number.

2121022221221 is a deficient number, since it is larger than the sum of its proper divisors (124781341939).

2121022221221 is a wasteful number, since it uses less digits than its factorization.

2121022221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 851623.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 2121022221221 its reverse (1221222201212), we get a palindrome (3342244422433).

The spelling of 2121022221221 in words is "two trillion, one hundred twenty-one billion, twenty-two million, two hundred twenty-one thousand, two hundred twenty-one".