840540 has 24 divisors (see below), whose sum is σ = 2353680. Its totient is φ = 224128.

The previous prime is 840523. The next prime is 840547. The reversal of 840540 is 45048.

840540 = T₄₀₅ + T₄₀₆ + ... + T₄₁₄.

840540 = 125² + 126² + ... + 164².

It is a plaindrome in base 13.

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 840540.

It is not an unprimeable number, because it can be changed into a prime (840547) by changing a digit.

840540 is an untouchable number, because it is not equal to the sum of proper divisors of any 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, 6945 + ... + 7064.

It is an arithmetic number, because the mean of its divisors is an integer number (98070).

2⁸⁴⁰⁵⁴⁰ is an apocalyptic number.

It is an amenable number.

840540 is an abundant number, since it is smaller than the sum of its proper divisors (1513140).

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

840540 is a wasteful number, since it uses less digits than its factorization.

840540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14021 (or 14019 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

The square root of 840540 is about 916.8096858127. The cubic root of 840540 is about 94.3740939638.

Adding to 840540 its reverse (45048), we get a palindrome (885588).

The spelling of 840540 in words is "eight hundred forty thousand, five hundred forty".