665646663 has 32 divisors (see below), whose sum is σ = 1018386432. Its totient is φ = 383011200.

The previous prime is 665646643. The next prime is 665646677. The reversal of 665646663 is 366646566.

It is not a de Polignac number, because 665646663 - 2¹⁸ = 665384519 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665646643) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48081 + ... + 60357.

It is an arithmetic number, because the mean of its divisors is an integer number (31824576).

Almost surely, 2^665646663 is an apocalyptic number.

665646663 is a deficient number, since it is larger than the sum of its proper divisors (352739769).

665646663 is a wasteful number, since it uses less digits than its factorization.

665646663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12375.

The product of its digits is 2799360, while the sum is 48.

The square root of 665646663 is about 25800.1291275838. The cubic root of 665646663 is about 873.1347096845.

The spelling of 665646663 in words is "six hundred sixty-five million, six hundred forty-six thousand, six hundred sixty-three".