646040 has 32 divisors (see below), whose sum is σ = 1503360. Its totient is φ = 249600.

The previous prime is 646039. The next prime is 646067. The reversal of 646040 is 40646.

It is a Harshad number since it is a multiple of its sum of digits (20).

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 7 ways as a sum of consecutive naturals, for example, 980 + ... + 1500.

It is an arithmetic number, because the mean of its divisors is an integer number (46980).

2⁶⁴⁶⁰⁴⁰ 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 646040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (751680).

646040 is an abundant number, since it is smaller than the sum of its proper divisors (857320).

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

646040 is a wasteful number, since it uses less digits than its factorization.

646040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563 (or 559 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 646040 is about 803.7661351413. The cubic root of 646040 is about 86.4476389088.

Adding to 646040 its reverse (40646), we get a palindrome (686686).

The spelling of 646040 in words is "six hundred forty-six thousand, forty".