400824 has 48 divisors (see below), whose sum is σ = 1146600. Its totient is φ = 126144.

The previous prime is 400823. The next prime is 400837. The reversal of 400824 is 428004.

Added to its reverse (428004) it gives a triangular number (828828 = T₁₂₈₇).

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 400797 and 400806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400823) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1222 + ... + 1514.

2⁴⁰⁰⁸²⁴ 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 400824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (573300).

400824 is an abundant number, since it is smaller than the sum of its proper divisors (745776).

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

400824 is a wasteful number, since it uses less digits than its factorization.

400824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324 (or 317 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 400824 is about 633.1066260907. The cubic root of 400824 is about 73.7311893039.

Adding to 400824 its reverse (428004), we get a palindrome (828828).

The spelling of 400824 in words is "four hundred thousand, eight hundred twenty-four".