21210322221 has 24 divisors (see below), whose sum is σ = 35388347904. Its totient is φ = 12098578560.

The previous prime is 21210322213. The next prime is 21210322249. The reversal of 21210322221 is 12222301212.

21210322221 is a `hidden beast` number, since 2 + 121 + 0 + 322 + 221 = 666.

It is not a de Polignac number, because 21210322221 - 2³ = 21210322213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210322194 and 21210322203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210320221) 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 23 ways as a sum of consecutive naturals, for example, 6299661 + ... + 6303026.

It is an arithmetic number, because the mean of its divisors is an integer number (1474514496).

Almost surely, 2^21210322221 is an apocalyptic number.

It is an amenable number.

21210322221 is a deficient number, since it is larger than the sum of its proper divisors (14178025683).

21210322221 is a wasteful number, since it uses less digits than its factorization.

21210322221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12602721 (or 12602718 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21210322221 its reverse (12222301212), we get a palindrome (33432623433).

The spelling of 21210322221 in words is "twenty-one billion, two hundred ten million, three hundred twenty-two thousand, two hundred twenty-one".