3661605865 has 8 divisors (see below), whose sum is σ = 4584967488. Its totient is φ = 2801924400.

The previous prime is 3661605853. The next prime is 3661605869. The reversal of 3661605865 is 5685061663.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3661605865 - 2⁵ = 3661605833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3661605869) 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, 15919911 + ... + 15920140.

It is an arithmetic number, because the mean of its divisors is an integer number (573120936).

Almost surely, 2^3661605865 is an apocalyptic number.

It is an amenable number.

3661605865 is a deficient number, since it is larger than the sum of its proper divisors (923361623).

3661605865 is a wasteful number, since it uses less digits than its factorization.

3661605865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31840079.

The product of its (nonzero) digits is 777600, while the sum is 46.

The square root of 3661605865 is about 60511.2044583480. The cubic root of 3661605865 is about 1541.3119007331.

The spelling of 3661605865 in words is "three billion, six hundred sixty-one million, six hundred five thousand, eight hundred sixty-five".