21332031221 has 2 divisors, whose sum is σ = 21332031222. Its totient is φ = 21332031220.

The previous prime is 21332031173. The next prime is 21332031251. The reversal of 21332031221 is 12213023312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12041770225 + 9290260996 = 109735^2 + 96386^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21332031221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21332031193 and 21332031202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21332031251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10666015610 + 10666015611.

It is an arithmetic number, because the mean of its divisors is an integer number (10666015611).

Almost surely, 2^21332031221 is an apocalyptic number.

It is an amenable number.

21332031221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21332031221 is an equidigital number, since it uses as much as digits as its factorization.

21332031221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21332031221 its reverse (12213023312), we get a palindrome (33545054533).

The spelling of 21332031221 in words is "twenty-one billion, three hundred thirty-two million, thirty-one thousand, two hundred twenty-one".