6663581 has 8 divisors (see below), whose sum is σ = 6853440. Its totient is φ = 6475392.

The previous prime is 6663557. The next prime is 6663593. The reversal of 6663581 is 1853666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6663581 - 2²² = 2469277 is a prime.

It is a super-2 number, since 2×6663581² = 88806623487122, 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 (6663511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14960 + ... + 15398.

It is an arithmetic number, because the mean of its divisors is an integer number (856680).

Almost surely, 2^6663581 is an apocalyptic number.

It is an amenable number.

6663581 is a deficient number, since it is larger than the sum of its proper divisors (189859).

6663581 is a wasteful number, since it uses less digits than its factorization.

6663581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 835.

The product of its digits is 25920, while the sum is 35.

The square root of 6663581 is about 2581.3912915325. The cubic root of 6663581 is about 188.1781640600.

The spelling of 6663581 in words is "six million, six hundred sixty-three thousand, five hundred eighty-one".