665456643 has 12 divisors (see below), whose sum is σ = 961440480. Its totient is φ = 443533776.

The previous prime is 665456641. The next prime is 665456657. The reversal of 665456643 is 346654566.

665456643 is a `hidden beast` number, since 6 + 6 + 545 + 66 + 43 = 666.

It is not a de Polignac number, because 665456643 - 2¹ = 665456641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665456641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 63430 + ... + 73172.

It is an arithmetic number, because the mean of its divisors is an integer number (80120040).

Almost surely, 2^665456643 is an apocalyptic number.

665456643 is a deficient number, since it is larger than the sum of its proper divisors (295983837).

665456643 is a wasteful number, since it uses less digits than its factorization.

665456643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17338 (or 17335 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 45.

The square root of 665456643 is about 25796.4463250270. The cubic root of 665456643 is about 873.0516181301.

The spelling of 665456643 in words is "six hundred sixty-five million, four hundred fifty-six thousand, six hundred forty-three".