4006661 has 2 divisors, whose sum is σ = 4006662. Its totient is φ = 4006660.

The previous prime is 4006649. The next prime is 4006687. The reversal of 4006661 is 1666004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3976036 + 30625 = 1994^2 + 175^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4006661 is a prime.

It is a Sophie Germain prime.

It is an Ulam number.

It is a Curzon number.

It is a nialpdrome in base 14.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4006621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2003330 + 2003331.

It is an arithmetic number, because the mean of its divisors is an integer number (2003331).

Almost surely, 2^4006661 is an apocalyptic number.

It is an amenable number.

4006661 is a deficient number, since it is larger than the sum of its proper divisors (1).

4006661 is an equidigital number, since it uses as much as digits as its factorization.

4006661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 4006661 is about 2001.6645573122. The cubic root of 4006661 is about 158.8281703181.

The spelling of 4006661 in words is "four million, six thousand, six hundred sixty-one".