🟦 first square number since 1936, last until 2116
🟦 first product of two two-digit squares since 1764, last until 2401
🟦 product of two different square pairs: 81 x 25 and 225 x 9. (So was 1764.)
🟦 only two prime factors: 3 and 5. The last year to consist of just 3s & 5s was 1875.
🟦 first square number since 1936, last until 2116
🟦 first product of two two-digit squares since 1764, last until 2401
🟦 product of two different square pairs: 81 x 25 and 225 x 9. (So was 1764.)
🟦 only two prime factors: 3 and 5. The last year to consist of just 3s & 5s was 1875.