1816840 has 32 divisors (see below), whose sum is σ = 4169880. Its totient is φ = 712192.

The previous prime is 1816831. The next prime is 1816849. The reversal of 1816840 is 486181.

1816840 = 341² + 342² + ... + 355².

1816840 is nontrivially palindromic in base 3.

It is an interprime number because it is at equal distance from previous prime (1816831) and next prime (1816849).

It can be written as a sum of positive squares in 4 ways, for example, as 1800964 + 15876 = 1342^2 + 126^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1816799 and 1816808.

It is not an unprimeable number, because it can be changed into a prime (1816849) 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, 1692 + ... + 2548.

2^1816840 is an apocalyptic number.

1816840 is a gapful number since it is divisible by the number (10) 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 1816840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2084940).

1816840 is an abundant number, since it is smaller than the sum of its proper divisors (2353040).

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

1816840 is a wasteful number, since it uses less digits than its factorization.

1816840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 921 (or 917 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 1816840 is about 1347.9020735944. The cubic root of 1816840 is about 122.0222122058.

It can be divided in two parts, 181 and 6840, that added together give a triangular number (7021 = T₁₁₈).

The spelling of 1816840 in words is "one million, eight hundred sixteen thousand, eight hundred forty".