21325203643421 has 2 divisors, whose sum is σ = 21325203643422. Its totient is φ = 21325203643420.

The previous prime is 21325203643409. The next prime is 21325203643459. The reversal of 21325203643421 is 12434630252312.

It is an a-pointer prime, because the next prime (21325203643459) can be obtained adding 21325203643421 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17480510140900 + 3844693502521 = 4180970^2 + 1960789^2 .

It is a cyclic number.

It is not a de Polignac number, because 21325203643421 - 2¹⁴ = 21325203627037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21325203643021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10662601821710 + 10662601821711.

It is an arithmetic number, because the mean of its divisors is an integer number (10662601821711).

Almost surely, 2^{21325203643421} is an apocalyptic number.

It is an amenable number.

21325203643421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21325203643421 is an equidigital number, since it uses as much as digits as its factorization.

21325203643421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 38.

Adding to 21325203643421 its reverse (12434630252312), we get a palindrome (33759833895733).

The spelling of 21325203643421 in words is "twenty-one trillion, three hundred twenty-five billion, two hundred three million, six hundred forty-three thousand, four hundred twenty-one".