840820 has 24 divisors (see below), whose sum is σ = 1870344. Its totient is φ = 316416.

The previous prime is 840817. The next prime is 840821. The reversal of 840820 is 28048.

840820 = T₉₆ + T₉₇ + ... + T₁₈₀.

840820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 266256 + 574564 = 516^2 + 758^2 .

It is a junction number, because it is equal to n+sod(n) for n = 840791 and 840800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 897 + ... + 1576.

It is an arithmetic number, because the mean of its divisors is an integer number (77931).

2⁸⁴⁰⁸²⁰ is an apocalyptic number.

It is an amenable number.

840820 is an abundant number, since it is smaller than the sum of its proper divisors (1029524).

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

840820 is a wasteful number, since it uses less digits than its factorization.

840820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2499 (or 2497 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

The square root of 840820 is about 916.9623765455. The cubic root of 840820 is about 94.3845720742.

Adding to 840820 its reverse (28048), we get a palindrome (868868).

The spelling of 840820 in words is "eight hundred forty thousand, eight hundred twenty".