6659661 has 4 divisors (see below), whose sum is σ = 8879552. Its totient is φ = 4439772.

The previous prime is 6659623. The next prime is 6659663. The reversal of 6659661 is 1669566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 6659661 - 2¹⁰ = 6658637 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6659663) 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 3 ways as a sum of consecutive naturals, for example, 1109941 + ... + 1109946.

It is an arithmetic number, because the mean of its divisors is an integer number (2219888).

Almost surely, 2^6659661 is an apocalyptic number.

It is an amenable number.

6659661 is a deficient number, since it is larger than the sum of its proper divisors (2219891).

6659661 is a wasteful number, since it uses less digits than its factorization.

6659661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2219890.

The product of its digits is 58320, while the sum is 39.

The square root of 6659661 is about 2580.6318993611. The cubic root of 6659661 is about 188.1412568226.

The spelling of 6659661 in words is "six million, six hundred fifty-nine thousand, six hundred sixty-one".