21021210011221 has 8 divisors (see below), whose sum is σ = 24199599430080. Its totient is φ = 17886660446688.

The previous prime is 21021210011213. The next prime is 21021210011233. The reversal of 21021210011221 is 12211001212012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21021210011221 - 2³ = 21021210011213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021210011195 and 21021210011204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021210011521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10959962551 + ... + 10959964468.

It is an arithmetic number, because the mean of its divisors is an integer number (3024949928760).

Almost surely, 2^{21021210011221} is an apocalyptic number.

It is an amenable number.

21021210011221 is a deficient number, since it is larger than the sum of its proper divisors (3178389418859).

21021210011221 is a wasteful number, since it uses less digits than its factorization.

21021210011221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21919927163.

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

Adding to 21021210011221 its reverse (12211001212012), we get a palindrome (33232211223233).

The spelling of 21021210011221 in words is "twenty-one trillion, twenty-one billion, two hundred ten million, eleven thousand, two hundred twenty-one".