665489497865 has 24 divisors (see below), whose sum is σ = 821276590680. Its totient is φ = 517683078720.

The previous prime is 665489497861. The next prime is 665489497877. The reversal of 665489497865 is 568794984566.

It can be written as a sum of positive squares in 12 ways, for example, as 7976097481 + 657513400384 = 89309^2 + 810872^2 .

It is not a de Polignac number, because 665489497865 - 2² = 665489497861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665489497861) 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, 410541755 + ... + 410543375.

It is an arithmetic number, because the mean of its divisors is an integer number (34219857945).

Almost surely, 2^665489497865 is an apocalyptic number.

It is an amenable number.

665489497865 is a deficient number, since it is larger than the sum of its proper divisors (155787092815).

665489497865 is an frugal number, since it uses more digits than its factorization.

665489497865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3358 (or 1663 counting only the distinct ones).

The product of its digits is 3135283200, while the sum is 77.

The spelling of 665489497865 in words is "six hundred sixty-five billion, four hundred eighty-nine million, four hundred ninety-seven thousand, eight hundred sixty-five".