8424 has 40 divisors (see below), whose sum is σ = 25410.
Its totient is φ = 2592.
The previous prime is 8423. The next prime is 8429. The reversal of 8424 is 4248.
It is a happy number.
It can be written as a sum of positive squares in only one way, i.e., 8100 + 324 = 90^2 + 18^2
It is a Harshad number since it is a multiple of its sum of digits (18).
It is a nude number because it is divisible by every one of its digits.
It is an Ulam number.
It is a junction number, because it is equal to n+sod(n) for n = 8397 and 8406.
It is not an unprimeable number, because it can be changed into a prime (8423) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (5) of ones.
It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 642 + ... + 654.
28424 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 8424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12705).
8424 is an abundant number, since it is smaller than the sum of its proper divisors (16986).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
8424 is a wasteful number, since it uses less digits than its factorization.
8424 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 31 (or 18 counting only the distinct ones).
The product of its digits is 256, while the sum is 18.
The square root of 8424 is about 91.7823512447.
The cubic root of 8424 is about 20.3472686581.
It can be divided in two parts, 84 and 24, that multiplied together give a triangular number (2016 = T63).
The spelling of 8424 in words is "eight thousand, four hundred twenty-four".