665940843 has 12 divisors (see below), whose sum is σ = 977684448. Its totient is φ = 436682160.

The previous prime is 665940829. The next prime is 665940851. The reversal of 665940843 is 348049566.

It is not a de Polignac number, because 665940843 - 2¹⁰ = 665939819 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665940893) 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, 605955 + ... + 607052.

It is an arithmetic number, because the mean of its divisors is an integer number (81473704).

Almost surely, 2^665940843 is an apocalyptic number.

665940843 is a deficient number, since it is larger than the sum of its proper divisors (311743605).

665940843 is a wasteful number, since it uses less digits than its factorization.

665940843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1213074 (or 1213071 counting only the distinct ones).

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

The square root of 665940843 is about 25805.8296320812. The cubic root of 665940843 is about 873.2633169237.

The spelling of 665940843 in words is "six hundred sixty-five million, nine hundred forty thousand, eight hundred forty-three".