665849579405 has 8 divisors (see below), whose sum is σ = 799024709112. Its totient is φ = 532676187648.

The previous prime is 665849579371. The next prime is 665849579407. The reversal of 665849579405 is 504975948566.

It can be written as a sum of positive squares in 4 ways, for example, as 39405823081 + 626443756324 = 198509^2 + 791482^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 665849579405 - 2¹⁶ = 665849513869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665849579407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 658217 + ... + 1328513.

It is an arithmetic number, because the mean of its divisors is an integer number (99878088639).

Almost surely, 2^665849579405 is an apocalyptic number.

It is an amenable number.

665849579405 is a deficient number, since it is larger than the sum of its proper divisors (133175129707).

665849579405 is a wasteful number, since it uses less digits than its factorization.

665849579405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 868975.

The product of its (nonzero) digits is 326592000, while the sum is 68.

The spelling of 665849579405 in words is "six hundred sixty-five billion, eight hundred forty-nine million, five hundred seventy-nine thousand, four hundred five".