664541665 has 8 divisors (see below), whose sum is σ = 805671720. Its totient is φ = 526152192.

The previous prime is 664541659. The next prime is 664541671. The reversal of 664541665 is 566145466.

664541665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (664541659) and next prime (664541671).

It can be written as a sum of positive squares in 4 ways, for example, as 93857344 + 570684321 = 9688^2 + 23889^2 .

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 664541665 - 2⁹ = 664541153 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 684610 + ... + 685579.

It is an arithmetic number, because the mean of its divisors is an integer number (100708965).

Almost surely, 2^664541665 is an apocalyptic number.

It is an amenable number.

664541665 is a deficient number, since it is larger than the sum of its proper divisors (141130055).

664541665 is a wasteful number, since it uses less digits than its factorization.

664541665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1370291.

The product of its digits is 518400, while the sum is 43.

The square root of 664541665 is about 25778.7056502067. The cubic root of 664541665 is about 872.6512968224.

The spelling of 664541665 in words is "six hundred sixty-four million, five hundred forty-one thousand, six hundred sixty-five".