16566531543 has 24 divisors (see below), whose sum is σ = 24092565120. Its totient is φ = 10969251840.

The previous prime is 16566531539. The next prime is 16566531557. The reversal of 16566531543 is 34513566561.

It is a happy number.

16566531543 is a `hidden beast` number, since 1 + 6 + 5 + 66 + 531 + 54 + 3 = 666.

It is not a de Polignac number, because 16566531543 - 2² = 16566531539 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16566531043) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1105978 + ... + 1120856.

It is an arithmetic number, because the mean of its divisors is an integer number (1003856880).

Almost surely, 2^16566531543 is an apocalyptic number.

16566531543 is a deficient number, since it is larger than the sum of its proper divisors (7526033577).

16566531543 is a wasteful number, since it uses less digits than its factorization.

16566531543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15719 (or 15716 counting only the distinct ones).

The product of its digits is 972000, while the sum is 45.

The spelling of 16566531543 in words is "sixteen billion, five hundred sixty-six million, five hundred thirty-one thousand, five hundred forty-three".