665985264 has 160 divisors (see below), whose sum is σ = 2112960000. Its totient is φ = 180182016.

The previous prime is 665985239. The next prime is 665985269. The reversal of 665985264 is 462589566.

Its product of digits (3110400) is a multiple of the sum of its prime divisors (2160).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665985269) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 311752 + ... + 313880.

It is an arithmetic number, because the mean of its divisors is an integer number (13206000).

Almost surely, 2^665985264 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 665985264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1056480000).

665985264 is an abundant number, since it is smaller than the sum of its proper divisors (1446974736).

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

665985264 is a wasteful number, since it uses less digits than its factorization.

665985264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2180 (or 2160 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 51.

The square root of 665985264 is about 25806.6902953478. The cubic root of 665985264 is about 873.2827332466.

The spelling of 665985264 in words is "six hundred sixty-five million, nine hundred eighty-five thousand, two hundred sixty-four".