665087661 has 12 divisors (see below), whose sum is σ = 1097922592. Its totient is φ = 380050056.

The previous prime is 665087641. The next prime is 665087663. The reversal of 665087661 is 166780566.

It is not a de Polignac number, because 665087661 - 2¹⁰ = 665086637 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 (665087663) 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 11 ways as a sum of consecutive naturals, for example, 5278411 + ... + 5278536.

Almost surely, 2^665087661 is an apocalyptic number.

It is an amenable number.

665087661 is a deficient number, since it is larger than the sum of its proper divisors (432834931).

665087661 is a wasteful number, since it uses less digits than its factorization.

665087661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10556960 (or 10556957 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 665087661 is about 25789.2935343332. The cubic root of 665087661 is about 872.8902252511.

The spelling of 665087661 in words is "six hundred sixty-five million, eighty-seven thousand, six hundred sixty-one".