21221031321 has 96 divisors (see below), whose sum is σ = 36979488000. Its totient is φ = 11911276800.

The previous prime is 21221031317. The next prime is 21221031347. The reversal of 21221031321 is 12313012212.

It is not a de Polignac number, because 21221031321 - 2² = 21221031317 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21221031294 and 21221031303.

It is not an unprimeable number, because it can be changed into a prime (21221031361) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 25597935 + ... + 25598763.

It is an arithmetic number, because the mean of its divisors is an integer number (385203000).

Almost surely, 2^21221031321 is an apocalyptic number.

21221031321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21221031321 is a deficient number, since it is larger than the sum of its proper divisors (15758456679).

21221031321 is a wasteful number, since it uses less digits than its factorization.

21221031321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1101 (or 1089 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21221031321 its reverse (12313012212), we get a palindrome (33534043533).

The spelling of 21221031321 in words is "twenty-one billion, two hundred twenty-one million, thirty-one thousand, three hundred twenty-one".