4005661 has 8 divisors (see below), whose sum is σ = 4390848. Its totient is φ = 3624000.

The previous prime is 4005653. The next prime is 4005691. The reversal of 4005661 is 1665004.

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 4005661 - 2³ = 4005653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4005691) 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, 1896 + ... + 3406.

It is an arithmetic number, because the mean of its divisors is an integer number (548856).

Almost surely, 2^4005661 is an apocalyptic number.

It is an amenable number.

4005661 is a deficient number, since it is larger than the sum of its proper divisors (385187).

4005661 is a wasteful number, since it uses less digits than its factorization.

4005661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1763.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 4005661 is about 2001.4147496209. The cubic root of 4005661 is about 158.8149555419.

The spelling of 4005661 in words is "four million, five thousand, six hundred sixty-one".