15624 has 48 divisors (see below), whose sum is σ = 49920. Its totient is φ = 4320.

The previous prime is 15619. The next prime is 15629. The reversal of 15624 is 42651.

It is a happy number.

15624 is nontrivially palindromic in base 5.

It is a Cunningham number, because it is equal to 5⁶-1.

It is an interprime number because it is at equal distance from previous prime (15619) and next prime (15629).

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

15624 is a nontrivial repdigit in base 5.

It is a plaindrome in base 5.

It is a nialpdrome in base 5.

It is a zygodrome in base 5.

It is a junction number, because it is equal to n+sod(n) for n = 15597 and 15606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15629) by changing a digit.

Being equal to 5×5⁵-1, it is a generalized Woodall number.

15624 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 11 ways as a sum of consecutive naturals, for example, 489 + ... + 519.

It is an arithmetic number, because the mean of its divisors is an integer number (1040).

15624 is a Friedman number, since it can be written as 5^(4+2)-1^6, using all its digits and the basic arithmetic operations.

2¹⁵⁶²⁴ is an apocalyptic number.

15624 is a gapful number since it is divisible by the number (14) 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 15624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24960).

15624 is an abundant number, since it is smaller than the sum of its proper divisors (34296).

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

15624 is a wasteful number, since it uses less digits than its factorization.

15624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50 (or 43 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 15624 is about 124.9959999360. The cubic root of 15624 is about 24.9994666553. Note that the first 3 decimals are identical.

15624 divided by its sum of digits (18) gives a palindrome (868).

It can be divided in two parts, 1 and 5624, that added together give a square (5625 = 75²).

The spelling of 15624 in words is "fifteen thousand, six hundred twenty-four".