21544344344473 has 2 divisors, whose sum is σ = 21544344344474. Its totient is φ = 21544344344472.

The previous prime is 21544344344431. The next prime is 21544344344557. The reversal of 21544344344473 is 37444344344512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17538230009689 + 4006114334784 = 4187867^2 + 2001528^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21544344344473 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21544344344473.

It is not a weakly prime, because it can be changed into another prime (21544344344773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10772172172236 + 10772172172237.

It is an arithmetic number, because the mean of its divisors is an integer number (10772172172237).

Almost surely, 2^{21544344344473} is an apocalyptic number.

It is an amenable number.

21544344344473 is a deficient number, since it is larger than the sum of its proper divisors (1).

21544344344473 is an equidigital number, since it uses as much as digits as its factorization.

21544344344473 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30965760, while the sum is 52.

Adding to 21544344344473 its reverse (37444344344512), we get a palindrome (58988688688985).

The spelling of 21544344344473 in words is "twenty-one trillion, five hundred forty-four billion, three hundred forty-four million, three hundred forty-four thousand, four hundred seventy-three".