This number is a composite.

+ 153 is equal to the alternating sum and difference of the squares of the integers from 1 to 153's largest prime factor, 17. [Cramer]

+ π(153) = π(15)*3!. [Gupta]

+ 153 is the sum of all the integers from 1 to 17 (seventeen is prime).

+ The largest known natural number n such that 2n does not contain the prime digit 3. It ends with 3, but also with the largest known prime number (53) with this property. [Capelle]

+ The sum of the factorial of digits of 153 is prime. [Bajpai]

+ The smaller member of a Ruth–Aaron pair; since the prime factors of 153 are 3 and 17, and the prime factors of 154 are 2, 7, and 11. Finally, 3 + 17 = 2 + 7 + 11. [Luen]

+ Smallest number in a set of three consecutive triangular numbers with three prime factors (counted with multiplicity). Note it is the only known number in the sequence which is not squarefree. [Gupta]

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