665860320 has 144 divisors (see below), whose sum is σ = 2391938640. Its totient is φ = 168210432.

The previous prime is 665860319. The next prime is 665860331. The reversal of 665860320 is 23068566.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15192 + ... + 39528.

It is an arithmetic number, because the mean of its divisors is an integer number (16610685).

Almost surely, 2^665860320 is an apocalyptic number.

665860320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665860320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1195969320).

665860320 is an abundant number, since it is smaller than the sum of its proper divisors (1726078320).

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

665860320 is a wasteful number, since it uses less digits than its factorization.

665860320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24377 (or 24366 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 665860320 is about 25804.2694141880. The cubic root of 665860320 is about 873.2281182935.

The spelling of 665860320 in words is "six hundred sixty-five million, eight hundred sixty thousand, three hundred twenty".