665588880 has 320 divisors, whose sum is σ = 2533766400. Its totient is φ = 159252480.

The previous prime is 665588863. The next prime is 665588923. The reversal of 665588880 is 88885566.

665588880 is a `hidden beast` number, since 6 + 6 + 558 + 8 + 8 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2589712 + ... + 2589968.

It is an arithmetic number, because the mean of its divisors is an integer number (7918020).

Almost surely, 2^665588880 is an apocalyptic number.

665588880 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 665588880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1266883200).

665588880 is an abundant number, since it is smaller than the sum of its proper divisors (1868177520).

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

665588880 is a wasteful number, since it uses less digits than its factorization.

665588880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399 (or 387 counting only the distinct ones).

The product of its (nonzero) digits is 3686400, while the sum is 54.

The square root of 665588880 is about 25799.0092833039. The cubic root of 665588880 is about 873.1094441266.

The spelling of 665588880 in words is "six hundred sixty-five million, five hundred eighty-eight thousand, eight hundred eighty".