665279120 has 80 divisors (see below), whose sum is σ = 1728639360. Its totient is φ = 236006400.

The previous prime is 665279107. The next prime is 665279171. The reversal of 665279120 is 21972566.

It is a happy number.

665279120 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26861 + ... + 45299.

It is an arithmetic number, because the mean of its divisors is an integer number (21607992).

Almost surely, 2^665279120 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665279120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (864319680).

665279120 is an abundant number, since it is smaller than the sum of its proper divisors (1063360240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665279120 is a wasteful number, since it uses less digits than its factorization.

665279120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18504 (or 18498 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 38.

The square root of 665279120 is about 25793.0052533628. The cubic root of 665279120 is about 872.9739769455.

The spelling of 665279120 in words is "six hundred sixty-five million, two hundred seventy-nine thousand, one hundred twenty".