840240 has 80 divisors (see below), whose sum is σ = 2901600. Its totient is φ = 223488.

The previous prime is 840239. The next prime is 840241. The reversal of 840240 is 42048.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (840239) and next prime (840241).

It is a tau number, because it is divible by the number of its divisors (80).

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

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (840241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1966 + ... + 2354.

It is an arithmetic number, because the mean of its divisors is an integer number (36270).

2⁸⁴⁰²⁴⁰ is an apocalyptic number.

840240 is a gapful number since it is divisible by the number (80) 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 840240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1450800).

840240 is an abundant number, since it is smaller than the sum of its proper divisors (2061360).

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

840240 is a wasteful number, since it uses less digits than its factorization.

840240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411 (or 399 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 840240 is about 916.6460603745. The cubic root of 840240 is about 94.3628648344.

Adding to 840240 its reverse (42048), we get a palindrome (882288).

The spelling of 840240 in words is "eight hundred forty thousand, two hundred forty".