665808740 has 48 divisors (see below), whose sum is σ = 1489994352. Its totient is φ = 249040896.

The previous prime is 665808739. The next prime is 665808763. The reversal of 665808740 is 47808566.

It can be written as a sum of positive squares in 8 ways, for example, as 3467044 + 662341696 = 1862^2 + 25736^2 .

It is a junction number, because it is equal to n+sod(n) for n = 665808691 and 665808700.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47144 + ... + 59616.

It is an arithmetic number, because the mean of its divisors is an integer number (31041549).

Almost surely, 2^665808740 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665808740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (744997176).

665808740 is an abundant number, since it is smaller than the sum of its proper divisors (824185612).

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

665808740 is a wasteful number, since it uses less digits than its factorization.

665808740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12656 (or 12654 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 44.

The square root of 665808740 is about 25803.2699478186. The cubic root of 665808740 is about 873.2055698860.

The spelling of 665808740 in words is "six hundred sixty-five million, eight hundred eight thousand, seven hundred forty".