21212132223221 has 16 divisors (see below), whose sum is σ = 21474744607680. Its totient is φ = 20950599196800.

The previous prime is 21212132223151. The next prime is 21212132223281. The reversal of 21212132223221 is 12232223121212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21212132223221 is a prime.

It is a super-2 number, since 2×21212132223221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212132223281) 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, 88773110 + ... + 89011736.

It is an arithmetic number, because the mean of its divisors is an integer number (1342171537980).

Almost surely, 2^{21212132223221} is an apocalyptic number.

It is an amenable number.

21212132223221 is a deficient number, since it is larger than the sum of its proper divisors (262612384459).

21212132223221 is a wasteful number, since it uses less digits than its factorization.

21212132223221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240884.

The product of its digits is 2304, while the sum is 26.

Adding to 21212132223221 its reverse (12232223121212), we get a palindrome (33444355344433).

It can be divided in two parts, 2121213 and 2223221, that added together give a palindrome (4344434).

The spelling of 21212132223221 in words is "twenty-one trillion, two hundred twelve billion, one hundred thirty-two million, two hundred twenty-three thousand, two hundred twenty-one".