21321031331221 has 64 divisors (see below), whose sum is σ = 23255496576000. Its totient is φ = 19493398020096.

The previous prime is 21321031331143. The next prime is 21321031331279. The reversal of 21321031331221 is 12213313012312.

It is not a de Polignac number, because 21321031331221 - 2¹⁵ = 21321031298453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321031334221) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 10570664005 + ... + 10570666021.

It is an arithmetic number, because the mean of its divisors is an integer number (363367134000).

Almost surely, 2^{21321031331221} is an apocalyptic number.

It is an amenable number.

21321031331221 is a deficient number, since it is larger than the sum of its proper divisors (1934465244779).

21321031331221 is a wasteful number, since it uses less digits than its factorization.

21321031331221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2998.

The product of its (nonzero) digits is 1296, while the sum is 25.

Adding to 21321031331221 its reverse (12213313012312), we get a palindrome (33534344343533).

The spelling of 21321031331221 in words is "twenty-one trillion, three hundred twenty-one billion, thirty-one million, three hundred thirty-one thousand, two hundred twenty-one".