21445123411543 has 32 divisors (see below), whose sum is σ = 23466545625600. Its totient is φ = 19477513984896.

The previous prime is 21445123411513. The next prime is 21445123411553. The reversal of 21445123411543 is 34511432154412.

It is a cyclic number.

It is not a de Polignac number, because 21445123411543 - 2²¹ = 21445121314391 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21445123411496 and 21445123411505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21445123411513) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3802998318 + ... + 3803003956.

It is an arithmetic number, because the mean of its divisors is an integer number (733329550800).

Almost surely, 2^{21445123411543} is an apocalyptic number.

21445123411543 is a deficient number, since it is larger than the sum of its proper divisors (2021422214057).

21445123411543 is a wasteful number, since it uses less digits than its factorization.

21445123411543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9991.

The product of its digits is 230400, while the sum is 40.

Adding to 21445123411543 its reverse (34511432154412), we get a palindrome (55956555565955).

The spelling of 21445123411543 in words is "twenty-one trillion, four hundred forty-five billion, one hundred twenty-three million, four hundred eleven thousand, five hundred forty-three".