665996961 has 8 divisors (see below), whose sum is σ = 1014852544. Its totient is φ = 380569680.

The previous prime is 665996941. The next prime is 665996971. The reversal of 665996961 is 169699566.

665996961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 665996961 - 2⁷ = 665996833 is a prime.

It is a super-2 number, since 2×665996961² = 887103904122471042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665996941) 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, 15857050 + ... + 15857091.

It is an arithmetic number, because the mean of its divisors is an integer number (126856568).

Almost surely, 2^665996961 is an apocalyptic number.

It is an amenable number.

665996961 is a deficient number, since it is larger than the sum of its proper divisors (348855583).

665996961 is a wasteful number, since it uses less digits than its factorization.

665996961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31714151.

The product of its digits is 4723920, while the sum is 57.

The square root of 665996961 is about 25806.9169216317. The cubic root of 665996961 is about 873.2878458364.

The spelling of 665996961 in words is "six hundred sixty-five million, nine hundred ninety-six thousand, nine hundred sixty-one".