21261556264343 has 2 divisors, whose sum is σ = 21261556264344. Its totient is φ = 21261556264342.

The previous prime is 21261556264339. The next prime is 21261556264409. The reversal of 21261556264343 is 34346265516212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21261556264343 - 2² = 21261556264339 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21261556264291 and 21261556264300.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21261556564343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10630778132171 + 10630778132172.

It is an arithmetic number, because the mean of its divisors is an integer number (10630778132172).

Almost surely, 2^{21261556264343} is an apocalyptic number.

21261556264343 is a deficient number, since it is larger than the sum of its proper divisors (1).

21261556264343 is an equidigital number, since it uses as much as digits as its factorization.

21261556264343 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6220800, while the sum is 50.

The spelling of 21261556264343 in words is "twenty-one trillion, two hundred sixty-one billion, five hundred fifty-six million, two hundred sixty-four thousand, three hundred forty-three".