21010212221 has 8 divisors (see below), whose sum is σ = 21287556864. Its totient is φ = 20733444160.

The previous prime is 21010212199. The next prime is 21010212257. The reversal of 21010212221 is 12221201012.

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 21010212221 - 2¹⁰ = 21010211197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010212196 and 21010212205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010212281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70541 + ... + 216786.

It is an arithmetic number, because the mean of its divisors is an integer number (2660944608).

Almost surely, 2^21010212221 is an apocalyptic number.

It is an amenable number.

21010212221 is a deficient number, since it is larger than the sum of its proper divisors (277344643).

21010212221 is an equidigital number, since it uses as much as digits as its factorization.

21010212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288291.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21010212221 its reverse (12221201012), we get a palindrome (33231413233).

The spelling of 21010212221 in words is "twenty-one billion, ten million, two hundred twelve thousand, two hundred twenty-one".