21321011221 has 8 divisors (see below), whose sum is σ = 21644863488. Its totient is φ = 20999370000.

The previous prime is 21321011171. The next prime is 21321011233. The reversal of 21321011221 is 12211012312.

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 21321011221 - 2²¹ = 21318914069 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21321011195 and 21321011204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321011251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 533325 + ... + 571906.

It is an arithmetic number, because the mean of its divisors is an integer number (2705607936).

Almost surely, 2^21321011221 is an apocalyptic number.

It is an amenable number.

21321011221 is a deficient number, since it is larger than the sum of its proper divisors (323852267).

21321011221 is a wasteful number, since it uses less digits than its factorization.

21321011221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1105523.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21321011221 its reverse (12211012312), we get a palindrome (33532023533).

The spelling of 21321011221 in words is "twenty-one billion, three hundred twenty-one million, eleven thousand, two hundred twenty-one".