21121102221221 has 16 divisors (see below), whose sum is σ = 22718693044224. Its totient is φ = 19588152758064.

The previous prime is 21121102221161. The next prime is 21121102221239. The reversal of 21121102221221 is 12212220112112.

It is not a de Polignac number, because 21121102221221 - 2¹⁴ = 21121102204837 is a prime.

It is a super-2 number, since 2×21121102221221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121102221193 and 21121102221202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121102221281) 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, 91185665 + ... + 91416998.

It is an arithmetic number, because the mean of its divisors is an integer number (1419918315264).

Almost surely, 2^{21121102221221} is an apocalyptic number.

It is an amenable number.

21121102221221 is a deficient number, since it is larger than the sum of its proper divisors (1597590823003).

21121102221221 is a wasteful number, since it uses less digits than its factorization.

21121102221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182602840.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21121102221221 its reverse (12212220112112), we get a palindrome (33333322333333).

The spelling of 21121102221221 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred two million, two hundred twenty-one thousand, two hundred twenty-one".