21621224006441 has 2 divisors, whose sum is σ = 21621224006442. Its totient is φ = 21621224006440.

The previous prime is 21621224006419. The next prime is 21621224006443. The reversal of 21621224006441 is 14460042212612.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15485799040000 + 6135424966441 = 3935200^2 + 2476979^2 .

It is a cyclic number.

It is not a de Polignac number, because 21621224006441 - 2³⁸ = 21346346099497 is a prime.

Together with 21621224006443, 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 (21621224006443) 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, 10810612003220 + 10810612003221.

It is an arithmetic number, because the mean of its divisors is an integer number (10810612003221).

Almost surely, 2^{21621224006441} is an apocalyptic number.

It is an amenable number.

21621224006441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21621224006441 is an equidigital number, since it uses as much as digits as its factorization.

21621224006441 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36864, while the sum is 35.

The spelling of 21621224006441 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred twenty-four million, six thousand, four hundred forty-one".