65781664 has 24 divisors (see below), whose sum is σ = 139470660. Its totient is φ = 30360576.

The previous prime is 65781647. The next prime is 65781691. The reversal of 65781664 is 46618756.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 60528400 + 5253264 = 7780^2 + 2292^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 65781664.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78649 + ... + 79480.

Almost surely, 2^65781664 is an apocalyptic number.

It is an amenable number.

65781664 is an abundant number, since it is smaller than the sum of its proper divisors (73688996).

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

65781664 is a wasteful number, since it uses less digits than its factorization.

65781664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158152 (or 158144 counting only the distinct ones).

The product of its digits is 241920, while the sum is 43.

The square root of 65781664 is about 8110.5896209832. The cubic root of 65781664 is about 403.6778793628.

The spelling of 65781664 in words is "sixty-five million, seven hundred eighty-one thousand, six hundred sixty-four".