64640320 has 28 divisors (see below), whose sum is σ = 153925524. Its totient is φ = 25856000.

The previous prime is 64640311. The next prime is 64640339. The reversal of 64640320 is 2304646.

It can be written as a sum of positive squares in 2 ways, for example, as 49336576 + 15303744 = 7024^2 + 3912^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 100681 + ... + 101320.

Almost surely, 2^64640320 is an apocalyptic number.

It is an amenable number.

64640320 is an abundant number, since it is smaller than the sum of its proper divisors (89285204).

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

64640320 is a wasteful number, since it uses less digits than its factorization.

64640320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202018 (or 202008 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 25.

The square root of 64640320 is about 8039.9203976159. The cubic root of 64640320 is about 401.3295756747.

Adding to 64640320 its reverse (2304646), we get a palindrome (66944966).

The spelling of 64640320 in words is "sixty-four million, six hundred forty thousand, three hundred twenty".