501840 has 120 divisors (see below), whose sum is σ = 1828008. Its totient is φ = 122880.

The previous prime is 501829. The next prime is 501841. The reversal of 501840 is 48105.

501840 = 90² + 91² + ... + 130².

It can be written as a sum of positive squares in 4 ways, for example, as 17424 + 484416 = 132^2 + 696^2 .

It is a tau number, because it is divible by the number of its divisors (120).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (501841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12220 + ... + 12260.

2⁵⁰¹⁸⁴⁰ 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 501840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (914004).

501840 is an abundant number, since it is smaller than the sum of its proper divisors (1326168).

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

501840 is a wasteful number, since it uses less digits than its factorization.

501840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 501840 is about 708.4066628710. The cubic root of 501840 is about 79.4672940108.

Adding to 501840 its reverse (48105), we get a palindrome (549945).

The spelling of 501840 in words is "five hundred one thousand, eight hundred forty".