4,100,625

Number
$4 \, 100 \, 625$ (four million, one hundred thousand, six hundred and twenty-five) is:


 * $3^8 \times 5^4$


 * The $4$th and last positive integer after $1$, $625$, $6561$ whose $4$th root equals the number of its divisors:
 * $\map \tau {4 \, 100 \, 625} = 45 = \sqrt [4] {4 \, 100 \, 625}$


 * The $45$th fourth power:
 * $4 \, 100 \, 625 = 45 \times 45 \times 45 \times 45$


 * The $2025$th square number:
 * $4 \, 100 \, 625 = 2025 \times 2025$