2661316665 has 24 divisors (see below), whose sum is σ = 4953309120. Its totient is φ = 1216601568.

The previous prime is 2661316661. The next prime is 2661316711. The reversal of 2661316665 is 5666131662.

It is not a de Polignac number, because 2661316665 - 2² = 2661316661 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2661316661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1809685 + ... + 1811154.

It is an arithmetic number, because the mean of its divisors is an integer number (206387880).

Almost surely, 2^2661316665 is an apocalyptic number.

It is an amenable number.

2661316665 is a deficient number, since it is larger than the sum of its proper divisors (2291992455).

2661316665 is a wasteful number, since it uses less digits than its factorization.

2661316665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3620861 (or 3620854 counting only the distinct ones).

The product of its digits is 233280, while the sum is 42.

The square root of 2661316665 is about 51587.9507734122. The cubic root of 2661316665 is about 1385.7945568362.

The spelling of 2661316665 in words is "two billion, six hundred sixty-one million, three hundred sixteen thousand, six hundred sixty-five".