665680320 has 168 divisors, whose sum is σ = 2351922144. Its totient is φ = 172689408.

The previous prime is 665680259. The next prime is 665680369. The reversal of 665680320 is 23086566.

665680320 is a `hidden beast` number, since 66 + 568 + 0 + 32 + 0 = 666.

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 polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 103437 + ... + 109683.

Almost surely, 2^665680320 is an apocalyptic number.

665680320 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 665680320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1175961072).

665680320 is an abundant number, since it is smaller than the sum of its proper divisors (1686241824).

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

665680320 is a wasteful number, since it uses less digits than its factorization.

665680320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6307 (or 6294 counting only the distinct ones).

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

The square root of 665680320 is about 25800.7813835163. The cubic root of 665680320 is about 873.1494254996.

The spelling of 665680320 in words is "six hundred sixty-five million, six hundred eighty thousand, three hundred twenty".