660665661 has 8 divisors (see below), whose sum is σ = 882698304. Its totient is φ = 439538400.

The previous prime is 660665653. The next prime is 660665669. The reversal of 660665661 is 166566066.

It is an interprime number because it is at equal distance from previous prime (660665653) and next prime (660665669).

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

It is not a de Polignac number, because 660665661 - 2³ = 660665653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660665669) by changing a digit.

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, 224640 + ... + 227561.

It is an arithmetic number, because the mean of its divisors is an integer number (110337288).

Almost surely, 2^660665661 is an apocalyptic number.

It is an amenable number.

660665661 is a deficient number, since it is larger than the sum of its proper divisors (222032643).

660665661 is a wasteful number, since it uses less digits than its factorization.

660665661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452691.

The product of its (nonzero) digits is 233280, while the sum is 42.

The square root of 660665661 is about 25703.4173019854. The cubic root of 660665661 is about 870.9513796482.

The spelling of 660665661 in words is "six hundred sixty million, six hundred sixty-five thousand, six hundred sixty-one".