6639748665 has 16 divisors (see below), whose sum is σ = 11589379776. Its totient is φ = 3219272000.

The previous prime is 6639748657. The next prime is 6639748669. The reversal of 6639748665 is 5668479366.

It is not a de Polignac number, because 6639748665 - 2³ = 6639748657 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 6639748599 and 6639748608.

It is not an unprimeable number, because it can be changed into a prime (6639748669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20120286 + ... + 20120615.

It is an arithmetic number, because the mean of its divisors is an integer number (724336236).

Almost surely, 2^6639748665 is an apocalyptic number.

It is an amenable number.

6639748665 is a deficient number, since it is larger than the sum of its proper divisors (4949631111).

6639748665 is a wasteful number, since it uses less digits than its factorization.

6639748665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40240920.

The product of its digits is 39191040, while the sum is 60.

The square root of 6639748665 is about 81484.6529415202. The cubic root of 6639748665 is about 1879.5355598806.

The spelling of 6639748665 in words is "six billion, six hundred thirty-nine million, seven hundred forty-eight thousand, six hundred sixty-five".