665386444800 has 3456 divisors, whose sum is σ = 3334286592000. Its totient is φ = 128198246400.

The previous prime is 665386444769. The next prime is 665386444841. The reversal of 665386444800 is 8444683566.

665386444800 is a `hidden beast` number, since 6 + 6 + 538 + 64 + 4 + 48 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (3456).

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

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 287 ways as a sum of consecutive naturals, for example, 14157158377 + ... + 14157158423.

It is an arithmetic number, because the mean of its divisors is an integer number (964782000).

Almost surely, 2^665386444800 is an apocalyptic number.

665386444800 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 665386444800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1667143296000).

665386444800 is an abundant number, since it is smaller than the sum of its proper divisors (2668900147200).

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

665386444800 is a wasteful number, since it uses less digits than its factorization.

665386444800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 13271040, while the sum is 54.

The spelling of 665386444800 in words is "six hundred sixty-five billion, three hundred eighty-six million, four hundred forty-four thousand, eight hundred".