665280999 has 16 divisors (see below), whose sum is σ = 995766240. Its totient is φ = 438946560.

The previous prime is 665280961. The next prime is 665281007. The reversal of 665280999 is 999082566.

It is not a de Polignac number, because 665280999 - 2¹¹ = 665278951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665280199) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 124392 + ... + 129629.

It is an arithmetic number, because the mean of its divisors is an integer number (62235390).

Almost surely, 2^665280999 is an apocalyptic number.

665280999 is a deficient number, since it is larger than the sum of its proper divisors (330485241).

665280999 is a wasteful number, since it uses less digits than its factorization.

665280999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254127 (or 254121 counting only the distinct ones).

The product of its (nonzero) digits is 2099520, while the sum is 54.

The square root of 665280999 is about 25793.0416779410. The cubic root of 665280999 is about 872.9747988143.

The spelling of 665280999 in words is "six hundred sixty-five million, two hundred eighty thousand, nine hundred ninety-nine".