Bitcoin is a peer-to-peer cryptocurrency proposed by Satoshi Nakamoto in 2008 and launched in 2009. Its supply is capped at 21 million, and its security has been tested for more than a decade. It is often called digital gold.
The cap is 21 million. By 2026 more than 19.7 million had been mined. The block reward halves about every four years, so new supply slows over time.
Bitcoin is the first widely used decentralized cryptocurrency. It was launched in 2009 by the pseudonymous Satoshi Nakamoto. A shared ledger lets people transfer value without a trusted intermediary.
The maximum is 21,000,000. The protocol does not add coins beyond that cap, which is why Bitcoin is treated as scarce.
You can transfer USDT and trade the BTC/USDT spot pair when it is listed. BTCUSDT perpetuals, if listed, can be used for long or short positions. The leverage available is the limit shown on that contract, not a fixed promise.