64440 has 48 divisors (see below), whose sum is σ = 210600. Its totient is φ = 17088.

The previous prime is 64439. The next prime is 64451. The reversal of 64440 is 4446.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 10 and base 16.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 64440.

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, 271 + ... + 449.

2⁶⁴⁴⁴⁰ is an apocalyptic number.

64440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105300).

64440 is an abundant number, since it is smaller than the sum of its proper divisors (146160).

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

64440 is a wasteful number, since it uses less digits than its factorization.

64440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 64440 is about 253.8503496157. The cubic root of 64440 is about 40.0914573959.

Adding to 64440 its reverse (4446), we get a palindrome (68886).

The spelling of 64440 in words is "sixty-four thousand, four hundred forty".