665606016605 has 4 divisors (see below), whose sum is σ = 798727219932. Its totient is φ = 532484813280.

The previous prime is 665606016601. The next prime is 665606016617. The reversal of 665606016605 is 506610606566.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 454563169369 + 211042847236 = 674213^2 + 459394^2 .

It is not a de Polignac number, because 665606016605 - 2² = 665606016601 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 665606016605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665606016601) 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, 66560601656 + ... + 66560601665.

It is an arithmetic number, because the mean of its divisors is an integer number (199681804983).

Almost surely, 2^665606016605 is an apocalyptic number.

It is an amenable number.

665606016605 is a deficient number, since it is larger than the sum of its proper divisors (133121203327).

665606016605 is a wasteful number, since it uses less digits than its factorization.

665606016605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133121203326.

The product of its (nonzero) digits is 1166400, while the sum is 47.

The spelling of 665606016605 in words is "six hundred sixty-five billion, six hundred six million, sixteen thousand, six hundred five".