665456339520 has 1344 divisors, whose sum is σ = 2847792729600. Its totient is φ = 139186667520.

The previous prime is 665456339489. The next prime is 665456339543. The reversal of 665456339520 is 25933654566.

It is a happy number.

665456339520 is a `hidden beast` number, since 6 + 6 + 54 + 5 + 63 + 3 + 9 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (1344).

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 191 ways as a sum of consecutive naturals, for example, 2905922766 + ... + 2905922994.

It is an arithmetic number, because the mean of its divisors is an integer number (2118893400).

Almost surely, 2^665456339520 is an apocalyptic number.

665456339520 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 665456339520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1423896364800).

665456339520 is an abundant number, since it is smaller than the sum of its proper divisors (2182336390080).

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

665456339520 is a wasteful number, since it uses less digits than its factorization.

665456339520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 476 (or 463 counting only the distinct ones).

The product of its (nonzero) digits is 17496000, while the sum is 54.

The spelling of 665456339520 in words is "six hundred sixty-five billion, four hundred fifty-six million, three hundred thirty-nine thousand, five hundred twenty".