665658539761 has 4 divisors (see below), whose sum is σ = 675034012224. Its totient is φ = 656283067300.

The previous prime is 665658539737. The next prime is 665658539771. The reversal of 665658539761 is 167935856566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 665658539761 - 2³¹ = 663511056113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665658539701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4687736125 + ... + 4687736266.

It is an arithmetic number, because the mean of its divisors is an integer number (168758503056).

Almost surely, 2^665658539761 is an apocalyptic number.

It is an amenable number.

665658539761 is a deficient number, since it is larger than the sum of its proper divisors (9375472463).

665658539761 is an equidigital number, since it uses as much as digits as its factorization.

665658539761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9375472462.

The product of its digits is 244944000, while the sum is 67.

The spelling of 665658539761 in words is "six hundred sixty-five billion, six hundred fifty-eight million, five hundred thirty-nine thousand, seven hundred sixty-one".