665366820 has 48 divisors (see below), whose sum is σ = 1864298688. Its totient is φ = 177310080.

The previous prime is 665366813. The next prime is 665366837. The reversal of 665366820 is 28663566.

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, 116430 + ... + 122010.

It is an arithmetic number, because the mean of its divisors is an integer number (38839556).

Almost surely, 2^665366820 is an apocalyptic number.

665366820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

665366820 is an abundant number, since it is smaller than the sum of its proper divisors (1198931868).

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

665366820 is a wasteful number, since it uses less digits than its factorization.

665366820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7580 (or 7578 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 42.

The square root of 665366820 is about 25794.7052706558. The cubic root of 665366820 is about 873.0123350078.

The spelling of 665366820 in words is "six hundred sixty-five million, three hundred sixty-six thousand, eight hundred twenty".