21101221021221 has 192 divisors, whose sum is σ = 35866202112000. Its totient is φ = 11828474064000.

The previous prime is 21101221021099. The next prime is 21101221021249. The reversal of 21101221021221 is 12212012210112.

21101221021221 is a `hidden beast` number, since 211 + 0 + 1 + 2 + 210 + 21 + 221 = 666.

It is not a de Polignac number, because 21101221021221 - 2¹³ = 21101221013029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21101221021194 and 21101221021203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101221023221) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2089431630 + ... + 2089441728.

It is an arithmetic number, because the mean of its divisors is an integer number (186803136000).

Almost surely, 2^{21101221021221} is an apocalyptic number.

It is an amenable number.

21101221021221 is a deficient number, since it is larger than the sum of its proper divisors (14764981090779).

21101221021221 is a wasteful number, since it uses less digits than its factorization.

21101221021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10452 (or 10449 counting only the distinct ones).

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

Adding to 21101221021221 its reverse (12212012210112), we get a palindrome (33313233231333).

The spelling of 21101221021221 in words is "twenty-one trillion, one hundred one billion, two hundred twenty-one million, twenty-one thousand, two hundred twenty-one".