665440440 has 128 divisors (see below), whose sum is σ = 2324712960. Its totient is φ = 149220864.

The previous prime is 665440423. The next prime is 665440453. The reversal of 665440440 is 44044566.

665440440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37047 + ... + 51993.

It is an arithmetic number, because the mean of its divisors is an integer number (18161820).

Almost surely, 2^665440440 is an apocalyptic number.

665440440 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 665440440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1162356480).

665440440 is an abundant number, since it is smaller than the sum of its proper divisors (1659272520).

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

665440440 is a wasteful number, since it uses less digits than its factorization.

665440440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15021 (or 15017 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 33.

The square root of 665440440 is about 25796.1322682297. The cubic root of 665440440 is about 873.0445321838.

The spelling of 665440440 in words is "six hundred sixty-five million, four hundred forty thousand, four hundred forty".