5666581 has 4 divisors (see below), whose sum is σ = 5746464. Its totient is φ = 5586700.

The previous prime is 5666561. The next prime is 5666599. The reversal of 5666581 is 1856665.

5666581 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1856665 = 5 ⋅371333.

It is a cyclic number.

It is not a de Polignac number, because 5666581 - 2¹⁵ = 5633813 is a prime.

It is a super-2 number, since 2×5666581² = 64220280459122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 5666581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5666501) 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, 39835 + ... + 39976.

It is an arithmetic number, because the mean of its divisors is an integer number (1436616).

Almost surely, 2^5666581 is an apocalyptic number.

It is an amenable number.

5666581 is a deficient number, since it is larger than the sum of its proper divisors (79883).

5666581 is an equidigital number, since it uses as much as digits as its factorization.

5666581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79882.

The product of its digits is 43200, while the sum is 37.

The square root of 5666581 is about 2380.4581491805. The cubic root of 5666581 is about 178.2818096318.

The spelling of 5666581 in words is "five million, six hundred sixty-six thousand, five hundred eighty-one".