812440 has 32 divisors (see below), whose sum is σ = 1926000. Its totient is φ = 307584.

The previous prime is 812431. The next prime is 812443. The reversal of 812440 is 44218.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (812443) by changing a digit.

812440 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 226 + ... + 1294.

2⁸¹²⁴⁴⁰ 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 812440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (963000).

812440 is an abundant number, since it is smaller than the sum of its proper divisors (1113560).

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

812440 is a wasteful number, since it uses less digits than its factorization.

812440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1099 (or 1095 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 812440 is about 901.3545362398. The cubic root of 812440 is about 93.3104819339.

Adding to 812440 its reverse (44218), we get a palindrome (856658).

The spelling of 812440 in words is "eight hundred twelve thousand, four hundred forty".