665642641313 has 24 divisors (see below), whose sum is σ = 801064024488. Its totient is φ = 547859179008.

The previous prime is 665642641291. The next prime is 665642641333. The reversal of 665642641313 is 313146246566.

It can be written as a sum of positive squares in 4 ways, for example, as 260679682624 + 404962958689 = 510568^2 + 636367^2 .

It is not a de Polignac number, because 665642641313 - 2¹² = 665642637217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665642641333) 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, 4091906 + ... + 4251467.

It is an arithmetic number, because the mean of its divisors is an integer number (33377667687).

Almost surely, 2^665642641313 is an apocalyptic number.

It is an amenable number.

665642641313 is a deficient number, since it is larger than the sum of its proper divisors (135421383175).

665642641313 is a wasteful number, since it uses less digits than its factorization.

665642641313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8343441 (or 8343422 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 47.

Adding to 665642641313 its reverse (313146246566), we get a palindrome (978788887879).

The spelling of 665642641313 in words is "six hundred sixty-five billion, six hundred forty-two million, six hundred forty-one thousand, three hundred thirteen".