665579520 has 312 divisors, whose sum is σ = 2422701216. Its totient is φ = 168689664.

The previous prime is 665579507. The next prime is 665579521. The reversal of 665579520 is 25975566.

665579520 is a `hidden beast` number, since 6 + 6 + 55 + 79 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665579521) 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 23 ways as a sum of consecutive naturals, for example, 4239282 + ... + 4239438.

It is an arithmetic number, because the mean of its divisors is an integer number (7765068).

Almost surely, 2^665579520 is an apocalyptic number.

665579520 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 665579520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1211350608).

665579520 is an abundant number, since it is smaller than the sum of its proper divisors (1757121696).

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

665579520 is a wasteful number, since it uses less digits than its factorization.

665579520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 567000, while the sum is 45.

The square root of 665579520 is about 25798.8278803515. The cubic root of 665579520 is about 873.1053513385.

The spelling of 665579520 in words is "six hundred sixty-five million, five hundred seventy-nine thousand, five hundred twenty".