6643543499 has 4 divisors (see below), whose sum is σ = 6643727160. Its totient is φ = 6643359840.

The previous prime is 6643543471. The next prime is 6643543507. The reversal of 6643543499 is 9943453466.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6643543499 - 2⁸ = 6643543243 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6643543499.

It is not an unprimeable number, because it can be changed into a prime (6643543469) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17534 + ... + 116595.

It is an arithmetic number, because the mean of its divisors is an integer number (1660931790).

Almost surely, 2^6643543499 is an apocalyptic number.

6643543499 is a deficient number, since it is larger than the sum of its proper divisors (183661).

6643543499 is a wasteful number, since it uses less digits than its factorization.

6643543499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183660.

The product of its digits is 8398080, while the sum is 53.

The square root of 6643543499 is about 81507.9351903850. The cubic root of 6643543499 is about 1879.8935637456.

The spelling of 6643543499 in words is "six billion, six hundred forty-three million, five hundred forty-three thousand, four hundred ninety-nine".