21325888721 has 2 divisors, whose sum is σ = 21325888722. Its totient is φ = 21325888720.

The previous prime is 21325888681. The next prime is 21325888723. The reversal of 21325888721 is 12788852312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11453280400 + 9872608321 = 107020^2 + 99361^2 .

It is a cyclic number.

It is not a de Polignac number, because 21325888721 - 2¹⁸ = 21325626577 is a prime.

Together with 21325888723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21325888723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10662944360 + 10662944361.

It is an arithmetic number, because the mean of its divisors is an integer number (10662944361).

Almost surely, 2^21325888721 is an apocalyptic number.

It is an amenable number.

21325888721 is a deficient number, since it is larger than the sum of its proper divisors (1).

21325888721 is an equidigital number, since it uses as much as digits as its factorization.

21325888721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 430080, while the sum is 47.

The spelling of 21325888721 in words is "twenty-one billion, three hundred twenty-five million, eight hundred eighty-eight thousand, seven hundred twenty-one".