1259

This number is a prime.

The first prime formed from the leading digits of the decimal expansion of the Delian constant (cube root of 2). [Gupta]

Twelve fifty-nine (12:59) is the largest "prime time" of day on a 12-hour clock in hours and minutes. (If you include seconds, it's 12:59:59.)

When a child has lived for 1259 days, for the first time, their age in days, weeks, months and years are all prime. The child would be 179 weeks old, that is, 41 months, or 3 years. [Hartley]

The smaller prime of the smallest pair of consecutive primes, i.e., (1259, 1277), whose sum of digits is prime and equal. [Gupta]

Smallest emirp partial sum of lucky numbers. [Post]

The smallest emirp using the end digits of each prime digit raised to a positive nonprime power: 2¹ = 2, 3⁶ = 729, 5¹ = 5, 7⁴ = 2401. [Beedassy]

There are exactly 1259 odd digits before the 1259th even digit of π. (1259 is the smallest prime making the previous statement true.) [Keith]

The only prime (emirp) equal to the sum of first n consecutive primes ending with 3 and smaller than a thousand, i.e., 3+13+23+...+193+223. Note that the number of terms is also emirp (n=13). [Loungrides]

There are exactly 1259 noncrossing golygons of length thirty-two. [Beedassy]

The largest concatenate emirp abcd from Ramanujan's classic paper that included a list of fifty-four quaternary (ax² + by² + cz² + du²) "diagonal" quadratic forms representing all integers. [Beedassy]

The smallest prime obtained by concatenating C^B and B^A, where A, B, C are three consecutive primes. [Leonardis]

1259 = 2^(2+3+5) + 235 is the only known prime of the form 2^(sum of first n primes) + concatenation of first n primes. [Sariyar]