21663411203321 has 4 divisors (see below), whose sum is σ = 21788633233572. Its totient is φ = 21538189173072.

The previous prime is 21663411203143. The next prime is 21663411203333. The reversal of 21663411203321 is 12330211436612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20261377597696 + 1402033605625 = 4501264^2 + 1184075^2 .

It is a cyclic number.

It is not a de Polignac number, because 21663411203321 - 2¹⁸ = 21663410941177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21663411203821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62611014866 + ... + 62611015211.

It is an arithmetic number, because the mean of its divisors is an integer number (5447158308393).

Almost surely, 2^{21663411203321} is an apocalyptic number.

It is an amenable number.

21663411203321 is a deficient number, since it is larger than the sum of its proper divisors (125222030251).

21663411203321 is a wasteful number, since it uses less digits than its factorization.

21663411203321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125222030250.

The product of its (nonzero) digits is 31104, while the sum is 35.

Adding to 21663411203321 its reverse (12330211436612), we get a palindrome (33993622639933).

The spelling of 21663411203321 in words is "twenty-one trillion, six hundred sixty-three billion, four hundred eleven million, two hundred three thousand, three hundred twenty-one".