212121111100221 has 24 divisors (see below), whose sum is σ = 313761848400000. Its totient is φ = 138055213213632.

The previous prime is 212121111100189. The next prime is 212121111100243. The reversal of 212121111100221 is 122001111121212.

It is a happy number.

212121111100221 is a `hidden beast` number, since 2 + 121 + 211 + 1 + 110 + 0 + 221 = 666.

It is not a de Polignac number, because 212121111100221 - 2⁵ = 212121111100189 is a prime.

It is a super-2 number, since 2×212121111100221² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 212121111100194 and 212121111100203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121111100721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1676014971 + ... + 1676141528.

It is an arithmetic number, because the mean of its divisors is an integer number (13073410350000).

Almost surely, 2^{212121111100221} is an apocalyptic number.

It is an amenable number.

212121111100221 is a deficient number, since it is larger than the sum of its proper divisors (101640737299779).

212121111100221 is a wasteful number, since it uses less digits than its factorization.

212121111100221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3352156673 (or 3352156670 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 212121111100221 its reverse (122001111121212), we get a palindrome (334122222221433).

The spelling of 212121111100221 in words is "two hundred twelve trillion, one hundred twenty-one billion, one hundred eleven million, one hundred thousand, two hundred twenty-one".