5666661 has 96 divisors (see below), whose sum is σ = 11950848. Its totient is φ = 2488320.

The previous prime is 5666641. The next prime is 5666677. The reversal of 5666661 is 1666665.

5666661 is nontrivially palindromic in base 16.

5666661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

5666661 is a nontrivial binomial coefficient, being equal to C(3367, 2).

It is not a de Polignac number, because 5666661 - 2¹³ = 5658469 is a prime.

It is a super-2 number, since 2×5666661² = 64222093777842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5666621) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 153135 + ... + 153171.

It is an arithmetic number, because the mean of its divisors is an integer number (124488).

Almost surely, 2^5666661 is an apocalyptic number.

5666661 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

5666661 is the 3366-th triangular number.

It is an amenable number.

5666661 is an abundant number, since it is smaller than the sum of its proper divisors (6284187).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

5666661 is a wasteful number, since it uses less digits than its factorization.

5666661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 88 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 5666661 is about 2380.4749526092. The cubic root of 5666661 is about 178.2826486137.

It can be divided in two parts, 566 and 6661, that added together give a palindrome (7227).

The spelling of 5666661 in words is "five million, six hundred sixty-six thousand, six hundred sixty-one".