21121102010221 has 4 divisors (see below), whose sum is σ = 21338845330012. Its totient is φ = 20903358690432.

The previous prime is 21121102010201. The next prime is 21121102010291. The reversal of 21121102010221 is 12201020112112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3063795136900 + 18057306873321 = 1750370^2 + 4249389^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121102010221 - 2¹¹ = 21121102008173 is a prime.

It is a super-2 number, since 2×21121102010221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121102010195 and 21121102010204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121102010201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108871659750 + ... + 108871659943.

It is an arithmetic number, because the mean of its divisors is an integer number (5334711332503).

Almost surely, 2^{21121102010221} is an apocalyptic number.

It is an amenable number.

21121102010221 is a deficient number, since it is larger than the sum of its proper divisors (217743319791).

21121102010221 is an equidigital number, since it uses as much as digits as its factorization.

21121102010221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217743319790.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21121102010221 its reverse (12201020112112), we get a palindrome (33322122122333).

The spelling of 21121102010221 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred two million, ten thousand, two hundred twenty-one".