3665840661 has 12 divisors (see below), whose sum is σ = 6051546592. Its totient is φ = 2094766056.

The previous prime is 3665840621. The next prime is 3665840681. The reversal of 3665840661 is 1660485663.

3665840661 is a `hidden beast` number, since 3 + 6 + 6 + 584 + 0 + 6 + 61 = 666.

It is not a de Polignac number, because 3665840661 - 2¹⁰ = 3665839637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3665840621) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29093911 + ... + 29094036.

Almost surely, 2^3665840661 is an apocalyptic number.

It is an amenable number.

3665840661 is a deficient number, since it is larger than the sum of its proper divisors (2385705931).

3665840661 is a wasteful number, since it uses less digits than its factorization.

3665840661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58187960 (or 58187957 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 3665840661 is about 60546.1861804689. The cubic root of 3665840661 is about 1541.9058684281.

The spelling of 3665840661 in words is "three billion, six hundred sixty-five million, eight hundred forty thousand, six hundred sixty-one".