1537

This number is a composite.

The only repfigit brilliant number with double-digit prime factors, i.e., 1537 = 29 × 53. Note that 2953 is prime and 5329 is a brilliant number, square of an emirp, i.e., 5329=73^2. [Loungrides]

Dropping this brilliant number's first and last digits yields its largest prime factor: 1537 = 29 * 53. [Post]

The smallest brilliant number that can be represented as the sum of first n April Fools primes, (case n=21), i.e., 9 + 21 + 27 + ... + 121 + 123 = 1537 = 29 × 53. Note that 2953 is prime. [Loungrides]