21266124218321 has 2 divisors, whose sum is σ = 21266124218322. Its totient is φ = 21266124218320.

The previous prime is 21266124218267. The next prime is 21266124218323. The reversal of 21266124218321 is 12381242166212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18598001251600 + 2668122966721 = 4312540^2 + 1633439^2 .

It is a cyclic number.

It is not a de Polignac number, because 21266124218321 - 2³⁰ = 21265050476497 is a prime.

Together with 21266124218323, 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 (21266124218323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10633062109160 + 10633062109161.

It is an arithmetic number, because the mean of its divisors is an integer number (10633062109161).

Almost surely, 2^{21266124218321} is an apocalyptic number.

It is an amenable number.

21266124218321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21266124218321 is an equidigital number, since it uses as much as digits as its factorization.

21266124218321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 110592, while the sum is 41.

The spelling of 21266124218321 in words is "twenty-one trillion, two hundred sixty-six billion, one hundred twenty-four million, two hundred eighteen thousand, three hundred twenty-one".