21556263162943 has 2 divisors, whose sum is σ = 21556263162944. Its totient is φ = 21556263162942.

The previous prime is 21556263162899. The next prime is 21556263162953. The reversal of 21556263162943 is 34926136265512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21556263162943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21556263162953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10778131581471 + 10778131581472.

It is an arithmetic number, because the mean of its divisors is an integer number (10778131581472).

Almost surely, 2^{21556263162943} is an apocalyptic number.

21556263162943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21556263162943 is an equidigital number, since it uses as much as digits as its factorization.

21556263162943 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13996800, while the sum is 55.

The spelling of 21556263162943 in words is "twenty-one trillion, five hundred fifty-six billion, two hundred sixty-three million, one hundred sixty-two thousand, nine hundred forty-three".