There are two reasons that make your total balance higher than the Max Send.
Sending bitcoin has a small fee. For example, if you have 10,000 satoshis and the network fee is 250 satoshis, then the maximum you can send to a recipient is 9,750 satoshis.
Tokens lock up satoshis. For each token output you have, a minimum of 546 satoshis are locked up. It is not uncommon that your entire balance is made of token-locked satoshis if people have sent you tokens but you have not received any tips or funded your account.
For example, if a user has received tokens through 5 separate transactions they would show a balance of 2,730 satoshis but it would be unspendable because they are all locked to tokens. To unlock the satoshis you would have to burn the tokens which most users do not want to do and Memo does not currently support.