665801568 has 36 divisors (see below), whose sum is σ = 1893374028. Its totient is φ = 221933760.

The previous prime is 665801567. The next prime is 665801573. The reversal of 665801568 is 865108566.

665801568 is a `hidden beast` number, since 6 + 6 + 5 + 80 + 1 + 568 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665801561) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1155618 + ... + 1156193.

It is an arithmetic number, because the mean of its divisors is an integer number (52593723).

Almost surely, 2^665801568 is an apocalyptic number.

It is an amenable number.

665801568 is an abundant number, since it is smaller than the sum of its proper divisors (1227572460).

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

665801568 is a wasteful number, since it uses less digits than its factorization.

665801568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2311827 (or 2311816 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The square root of 665801568 is about 25803.1309728103. The cubic root of 665801568 is about 873.2024345248.

The spelling of 665801568 in words is "six hundred sixty-five million, eight hundred one thousand, five hundred sixty-eight".