6643441505 has 4 divisors (see below), whose sum is σ = 7972129812. Its totient is φ = 5314753200.

The previous prime is 6643441499. The next prime is 6643441507. The reversal of 6643441505 is 5051443466.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2094343696 + 4549097809 = 45764^2 + 67447^2 .

It is not a de Polignac number, because 6643441505 - 2⁴ = 6643441489 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6643441507) 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, 664344146 + ... + 664344155.

It is an arithmetic number, because the mean of its divisors is an integer number (1993032453).

Almost surely, 2^6643441505 is an apocalyptic number.

It is an amenable number.

6643441505 is a deficient number, since it is larger than the sum of its proper divisors (1328688307).

6643441505 is a wasteful number, since it uses less digits than its factorization.

6643441505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1328688306.

The product of its (nonzero) digits is 172800, while the sum is 38.

The square root of 6643441505 is about 81507.3095188401. The cubic root of 6643441505 is about 1879.8839434355.

The spelling of 6643441505 in words is "six billion, six hundred forty-three million, four hundred forty-one thousand, five hundred five".