21203276621 has 2 divisors, whose sum is σ = 21203276622. Its totient is φ = 21203276620.

The previous prime is 21203276609. The next prime is 21203276623. The reversal of 21203276621 is 12667230212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18985808521 + 2217468100 = 137789^2 + 47090^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203276621 - 2²⁶ = 21136167757 is a prime.

It is a Sophie Germain prime.

Together with 21203276623, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21203276623) 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, 10601638310 + 10601638311.

It is an arithmetic number, because the mean of its divisors is an integer number (10601638311).

Almost surely, 2^21203276621 is an apocalyptic number.

It is an amenable number.

21203276621 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203276621 is an equidigital number, since it uses as much as digits as its factorization.

21203276621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 32.

The spelling of 21203276621 in words is "twenty-one billion, two hundred three million, two hundred seventy-six thousand, six hundred twenty-one".