665814820 has 24 divisors (see below), whose sum is σ = 1525321728. Its totient is φ = 242114400.

The previous prime is 665814791. The next prime is 665814827. The reversal of 665814820 is 28418566.

It is not an unprimeable number, because it can be changed into a prime (665814827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1512996 + ... + 1513435.

It is an arithmetic number, because the mean of its divisors is an integer number (63555072).

Almost surely, 2^665814820 is an apocalyptic number.

It is an amenable number.

665814820 is an abundant number, since it is smaller than the sum of its proper divisors (859506908).

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

665814820 is a wasteful number, since it uses less digits than its factorization.

665814820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3026451 (or 3026449 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 40.

The square root of 665814820 is about 25803.3877620750. The cubic root of 665814820 is about 873.2082278434.

The spelling of 665814820 in words is "six hundred sixty-five million, eight hundred fourteen thousand, eight hundred twenty".