A cushy number
Definition 1 of 1
Pro Tip 1/3Colloquial Use
This phrase is casual and might not suit formal or professional conversations. 
My uncle's new job is a cushy number; he's thrilled.
Pro Tip 2/3Slightly Envious
People might use the phrase with a touch of jealousy, as it implies an easy life. 
She's got such a cushy number at work, comes and goes as she pleases.
Pro Tip 3/3British Origin
The phrase is primarily used in the UK, so it might not be understood everywhere. 
When I told my Canadian friend about my cushy number, he had no clue what I meant.