21322814409821 has 2 divisors, whose sum is σ = 21322814409822. Its totient is φ = 21322814409820.

The previous prime is 21322814409779. The next prime is 21322814409881. The reversal of 21322814409821 is 12890441822312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20990957764921 + 331856644900 = 4581589^2 + 576070^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21322814409821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21322814409881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10661407204910 + 10661407204911.

It is an arithmetic number, because the mean of its divisors is an integer number (10661407204911).

Almost surely, 2^{21322814409821} is an apocalyptic number.

It is an amenable number.

21322814409821 is a deficient number, since it is larger than the sum of its proper divisors (1).

21322814409821 is an equidigital number, since it uses as much as digits as its factorization.

21322814409821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 442368, while the sum is 47.

The spelling of 21322814409821 in words is "twenty-one trillion, three hundred twenty-two billion, eight hundred fourteen million, four hundred nine thousand, eight hundred twenty-one".