840840 has 192 divisors, whose sum is σ = 3447360. Its totient is φ = 161280.

The previous prime is 840839. The next prime is 840841. The reversal of 840840 is 48048.

It is an interprime number because it is at equal distance from previous prime (840839) and next prime (840841).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 840840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840841) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 64674 + ... + 64686.

It is an arithmetic number, because the mean of its divisors is an integer number (17955).

2⁸⁴⁰⁸⁴⁰ 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 840840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1723680).

840840 is an abundant number, since it is smaller than the sum of its proper divisors (2606520).

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

840840 is a wasteful number, since it uses less digits than its factorization.

840840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 24.

The square root of 840840 is about 916.9732820535. The cubic root of 840840 is about 94.3853204216.

Adding to 840840 its reverse (48048), we get a palindrome (888888).

It can be divided in two parts, 8408 and 40, that added together give a palindrome (8448).

The spelling of 840840 in words is "eight hundred forty thousand, eight hundred forty".