21211010221221 has 6 divisors (see below), whose sum is σ = 30638125875110. Its totient is φ = 14140673480808.

The previous prime is 21211010221199. The next prime is 21211010221231. The reversal of 21211010221221 is 12212201011212.

21211010221221 is a `hidden beast` number, since 2 + 1 + 211 + 0 + 10 + 221 + 221 = 666.

It can be written as a sum of positive squares in only one way, i.e., 17217063929025 + 3993946292196 = 4149345^2 + 1998486^2 .

It is not a de Polignac number, because 21211010221221 - 2⁵ = 21211010221189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211010221194 and 21211010221203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211010221231) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1178389456726 + ... + 1178389456743.

Almost surely, 2^{21211010221221} is an apocalyptic number.

It is an amenable number.

21211010221221 is a deficient number, since it is larger than the sum of its proper divisors (9427115653889).

21211010221221 is a wasteful number, since it uses less digits than its factorization.

21211010221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2356778913475 (or 2356778913472 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21211010221221 its reverse (12212201011212), we get a palindrome (33423211232433).

The spelling of 21211010221221 in words is "twenty-one trillion, two hundred eleven billion, ten million, two hundred twenty-one thousand, two hundred twenty-one".