65680640 has 108 divisors (see below), whose sum is σ = 166158804. Its totient is φ = 24870912.

The previous prime is 65680633. The next prime is 65680691. The reversal of 65680640 is 4608656.

It can be written as a sum of positive squares in 2 ways, for example, as 26543104 + 39137536 = 5152^2 + 6256^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 65680640.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 677072 + ... + 677168.

Almost surely, 2^65680640 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 65680640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83079402).

65680640 is an abundant number, since it is smaller than the sum of its proper divisors (100478164).

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

65680640 is an equidigital number, since it uses as much as digits as its factorization.

65680640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 65680640 is about 8104.3593207606. The cubic root of 65680640 is about 403.4711244408.

The spelling of 65680640 in words is "sixty-five million, six hundred eighty thousand, six hundred forty".