665938560 has 128 divisors (see below), whose sum is σ = 2425968000. Its totient is φ = 152211456.

The previous prime is 665938517. The next prime is 665938583. The reversal of 665938560 is 65839566.

It is a tau number, because it is divible by the number of its divisors (128).

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11335 + ... + 38214.

It is an arithmetic number, because the mean of its divisors is an integer number (18952875).

Almost surely, 2^665938560 is an apocalyptic number.

665938560 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

665938560 is an abundant number, since it is smaller than the sum of its proper divisors (1760029440).

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

665938560 is a wasteful number, since it uses less digits than its factorization.

665938560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49578 (or 49566 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 48.

The square root of 665938560 is about 25805.7853978522. The cubic root of 665938560 is about 873.2623190060.

The spelling of 665938560 in words is "six hundred sixty-five million, nine hundred thirty-eight thousand, five hundred sixty".