665582400 has 672 divisors, whose sum is σ = 2902671360. Its totient is φ = 145152000.

The previous prime is 665582399. The next prime is 665582417. The reversal of 665582400 is 4285566.

665582400 is a `hidden beast` number, since 66 + 558 + 2 + 40 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9374365 + ... + 9374435.

Almost surely, 2^665582400 is an apocalyptic number.

665582400 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 665582400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1451335680).

665582400 is an abundant number, since it is smaller than the sum of its proper divisors (2237088960).

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

665582400 is a wasteful number, since it uses less digits than its factorization.

665582400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 665582400 is about 25798.8836967804. The cubic root of 665582400 is about 873.1066106620.

Adding to 665582400 its product of nonzero digits (57600), we get a square (665640000 = 25800²).

The spelling of 665582400 in words is "six hundred sixty-five million, five hundred eighty-two thousand, four hundred".