6643659 has 16 divisors (see below), whose sum is σ = 9757440. Its totient is φ = 3987360.

The previous prime is 6643649. The next prime is 6643667. The reversal of 6643659 is 9563466.

It is a happy number.

It is not a de Polignac number, because 6643659 - 2¹³ = 6635467 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (6643649) 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, 2674 + ... + 4520.

It is an arithmetic number, because the mean of its divisors is an integer number (609840).

Almost surely, 2^6643659 is an apocalyptic number.

6643659 is a deficient number, since it is larger than the sum of its proper divisors (3113781).

6643659 is a wasteful number, since it uses less digits than its factorization.

6643659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1970.

The product of its digits is 116640, while the sum is 39.

The square root of 6643659 is about 2577.5296312555. The cubic root of 6643659 is about 187.9904457948.

The spelling of 6643659 in words is "six million, six hundred forty-three thousand, six hundred fifty-nine".