How do I validate a number field so an error appears if an user enters a string?

[alealpha2000]

I have a validation schema like this:

'PrecioUnitario': Yup.number().nullable().min(0, 'El precio unitario debe ser mayor a 0'),

And I use but no error message appears. If an user enters a string a null value is sent instead. How do I add an error when a user enters a string?