64840 has 16 divisors (see below), whose sum is σ = 145980. Its totient is φ = 25920.

The previous prime is 64817. The next prime is 64849. The reversal of 64840 is 4846.

It can be written as a sum of positive squares in 2 ways, for example, as 64516 + 324 = 254^2 + 18^2 .

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (64849) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 771 + ... + 850.

2⁶⁴⁸⁴⁰ is an apocalyptic number.

It is an amenable number.

64840 is an abundant number, since it is smaller than the sum of its proper divisors (81140).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72990).

64840 is a wasteful number, since it uses less digits than its factorization.

64840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632 (or 1628 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 64840 is about 254.6369965264. The cubic root of 64840 is about 40.1742399093.

The spelling of 64840 in words is "sixty-four thousand, eight hundred forty".