She will keep 1000000 / 2 = <<1000000/2=500000>>500000 Safe Moon tokens for herself.
For the remaining siblings, they will each receive 500000 / 4 = <<500000/4=125000>>125000 tokens.
This means that Sandy will have 500000 - 125000 = <<500000-125000=375000>>375000 tokens more than any of her siblings.
#### 375000