21221020111221 has 32 divisors (see below), whose sum is σ = 35937381638400. Its totient is φ = 12123728110080.

The previous prime is 21221020111201. The next prime is 21221020111243. The reversal of 21221020111221 is 12211102012212.

21221020111221 is a `hidden beast` number, since 21 + 2 + 210 + 201 + 11 + 221 = 666.

It is not a de Polignac number, because 21221020111221 - 2¹⁹ = 21221019586933 is a prime.

It is a super-2 number, since 2×21221020111221² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21221020111194 and 21221020111203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221020111201) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10999336 + ... + 12783873.

It is an arithmetic number, because the mean of its divisors is an integer number (1123043176200).

Almost surely, 2^{21221020111221} is an apocalyptic number.

21221020111221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21221020111221 is a deficient number, since it is larger than the sum of its proper divisors (14716361527179).

21221020111221 is a wasteful number, since it uses less digits than its factorization.

21221020111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23787946 (or 23787940 counting only the distinct ones).

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

Adding to 21221020111221 its reverse (12211102012212), we get a palindrome (33432122123433).

The spelling of 21221020111221 in words is "twenty-one trillion, two hundred twenty-one billion, twenty million, one hundred eleven thousand, two hundred twenty-one".