4900

Number
$4900$ (four thousand nine hundred) is:


 * $2^2 \times 5^2 \times 7^2$


 * The $70$th square number:
 * $4900 = 70 \times 70$


 * The $24$th square pyramidal number:
 * $4900 = 1^2 + 2^2 + \cdots + 24^2$