6659581 has 6 divisors (see below), whose sum is σ = 6962270. Its totient is φ = 6369528.

The previous prime is 6659579. The next prime is 6659591. The reversal of 6659581 is 1859566.

It can be written as a sum of positive squares in only one way, i.e., 4284900 + 2374681 = 2070^2 + 1541^2 .

It is not a de Polignac number, because 6659581 - 2¹ = 6659579 is a prime.

It is a super-2 number, since 2×6659581² = 88700038191122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6659501) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5766 + ... + 6823.

Almost surely, 2^6659581 is an apocalyptic number.

It is an amenable number.

6659581 is a deficient number, since it is larger than the sum of its proper divisors (302689).

6659581 is a wasteful number, since it uses less digits than its factorization.

6659581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12635 (or 12612 counting only the distinct ones).

The product of its digits is 64800, while the sum is 40.

The square root of 6659581 is about 2580.6163992349. The cubic root of 6659581 is about 188.1405034629.

The spelling of 6659581 in words is "six million, six hundred fifty-nine thousand, five hundred eighty-one".