邹赛尔数（Zeisel number）是一种无平方数因数的数，而且至少有三个质因数可以用下式表示：

其中a和b是整数的系数，而x为在因数分解后将质因数由小到大排列后所得的编号，另外令。头几个邹赛尔数是：

以1729为例，1729是邹赛尔数，对应的系数是a = 1和b = 6。其质因数7,13和19可以用下式表示：

A Zeisel number, named after Helmut Zeisel, is a square-free integer k with at least three prime factors which fall into the pattern

where a and b are some integer constants and x is the index number of each prime factor in the factorization, sorted from lowest to highest. For the purpose of determining Zeisel numbers, . The first few Zeisel numbers are