21121332221 has 16 divisors (see below), whose sum is σ = 23331369600. Its totient is φ = 18960506880.

The previous prime is 21121332217. The next prime is 21121332227. The reversal of 21121332221 is 12223312112.

It is a cyclic number.

It is not a de Polignac number, because 21121332221 - 2² = 21121332217 is a prime.

It is a super-2 number, since 2×21121332221² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121332193 and 21121332202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121332227) 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, 457040 + ... + 501126.

It is an arithmetic number, because the mean of its divisors is an integer number (1458210600).

Almost surely, 2^21121332221 is an apocalyptic number.

It is an amenable number.

21121332221 is a deficient number, since it is larger than the sum of its proper divisors (2210037379).

21121332221 is a wasteful number, since it uses less digits than its factorization.

21121332221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44644.

The product of its digits is 288, while the sum is 20.

Adding to 21121332221 its reverse (12223312112), we get a palindrome (33344644333).

The spelling of 21121332221 in words is "twenty-one billion, one hundred twenty-one million, three hundred thirty-two thousand, two hundred twenty-one".