# System entities

The Hedera network reserves the first
[`ledger.numReservedSystemEntities=1000`](../hedera-mono-service/src/main/resources/bootstrap.properties)
entity numbers for its own uses.

An account with a number in the reserved range is called a **system account**.
A file with a number in the reserved range is called a **system file**. 

The entity numbers for system accounts and files are fixed, for the network,
in [`bootstrap.properties`](../hedera-mono-service/src/main/resources/bootstrap.properties).

See also [`privileged-transactions.md`](privileged-transactions.md) for the semantics of these system entities.

## System accounts

| Account   |Name|
|:----------|:---|
| `0.0.2`   |`accounts.treasury`|
| `0.0.50`  |`accounts.systemAdmin`|
| `0.0.55`  |`accounts.addressBookAdmin`|
| `0.0.57`  |`accounts.exchangeRatesAdmin`|
| `0.0.58`  |`accounts.freezeAdmin`|
| `0.0.59`  |`accounts.systemDeleteAdmin`|
| `0.0.60`  |`accounts.systemUndeleteAdmin`|
| `0.0.800` |`accounts.stakingRewardAccount`|
| `0.0.801` |`accounts.nodeRewardAccount`|



## System files

| File|Name|
|:---|:---|
|`0.0.101`|`files.addressBook`|
|`0.0.102`|`files.nodeDetails`|
|`0.0.111`|`files.feeSchedules`|
|`0.0.112`|`files.exchangeRates`|
|`0.0.121`|`files.networkProperties`|
|`0.0.122`|`files.hapiPermissions`|
|`0.0.123`|`files.throttleDefinitions`|
|`0.0.150`..`0.0.159`|`files.softwareUpdate` (range of 10 files)|


## System contract addresses
| Address₁₆| Address₁₀ | Name                 |
|:--------|:----------|:---------------------|
| `0x167` | `359`     | Hedera Token Service |
| `0x168` | `360`     | Exchange Rate        |
| `0x169` | `361`     | PRNG                 |
