840456 has 40 divisors (see below), whose sum is σ = 2355870. Its totient is φ = 279936.

The previous prime is 840451. The next prime is 840457. The reversal of 840456 is 654048.

840456 is a nontrivial binomial coefficient, being equal to C(1297, 2).

It can be written as a sum of positive squares in only one way, i.e., 443556 + 396900 = 666^2 + 630^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840451) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1 + ... + 1296.

2⁸⁴⁰⁴⁵⁶ is an apocalyptic number.

840456 is the 1296-th triangular number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 840456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1177935).

840456 is an abundant number, since it is smaller than the sum of its proper divisors (1515414).

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

840456 is a wasteful number, since it uses less digits than its factorization.

840456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1315 (or 1302 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 840456 is about 916.7638736338. The cubic root of 840456 is about 94.3709500769.

It can be divided in two parts, 840 and 456, that added together give a 4-th power (1296 = 6⁴).

The spelling of 840456 in words is "eight hundred forty thousand, four hundred fifty-six".