6691663 has 12 divisors (see below), whose sum is σ = 7612920. Its totient is φ = 5870480.

The previous prime is 6691661. The next prime is 6691687. The reversal of 6691663 is 3661966.

6691663 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 6691663 - 2¹ = 6691661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6691661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2556 + ... + 4462.

It is an arithmetic number, because the mean of its divisors is an integer number (634410).

Almost surely, 2^6691663 is an apocalyptic number.

6691663 is a deficient number, since it is larger than the sum of its proper divisors (921257).

6691663 is a wasteful number, since it uses less digits than its factorization.

6691663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1958 (or 1947 counting only the distinct ones).

The product of its digits is 34992, while the sum is 37.

The square root of 6691663 is about 2586.8248877727. The cubic root of 6691663 is about 188.4421369021.

It can be divided in two parts, 669 and 1663, that added together give a palindrome (2332).

The spelling of 6691663 in words is "six million, six hundred ninety-one thousand, six hundred sixty-three".