665656505 has 8 divisors (see below), whose sum is σ = 845775432. Its totient is φ = 501200128.

The previous prime is 665656493. The next prime is 665656567. The reversal of 665656505 is 505656566.

It can be written as a sum of positive squares in 4 ways, for example, as 208167184 + 457489321 = 14428^2 + 21389^2 .

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 665656505 - 2²⁰ = 664607929 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3915542 + ... + 3915711.

It is an arithmetic number, because the mean of its divisors is an integer number (105721929).

Almost surely, 2^665656505 is an apocalyptic number.

It is an amenable number.

665656505 is a deficient number, since it is larger than the sum of its proper divisors (180118927).

665656505 is a wasteful number, since it uses less digits than its factorization.

665656505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7831275.

The product of its (nonzero) digits is 810000, while the sum is 44.

The square root of 665656505 is about 25800.3198623583. The cubic root of 665656505 is about 873.1390129432.

The spelling of 665656505 in words is "six hundred sixty-five million, six hundred fifty-six thousand, five hundred five".