IsMachineNumber

Whether expr is an ordinary (not extended-precision) inexact number.

✓ checked against that system · ! checked, with disagreements (hover a chip)Wolfram LanguageMachineNumberQ✓

IsMachineNumber(expr)

True

for an inexact number carrying at most 17 significant decimal digits,

False

otherwise (including every exact number).

Typed signatures

Type	Package	Applies
`(any) -> boolean`	`combinatorics`	always

Domain: Collections

Details

Wolfram spells this MachineNumberQ; renamed to the Is… convention used across compute-engine predicates.
Compute engine keeps no separate "machine" number representation — every inexact value is a decimal carrying as many digits as it was given — so this is approximated by digit count: a literal of up to 17 digits, as Wolfram reads it, is a machine number.