Add-Type -AssemblyName ("Sap.Data.SQLAnywhere.v4.5, Version=17.0.0.10624, Culture=neutral, PublicKeyToken=f222fc4333e0d400")

[bigint] $myvalue = 123456789123456789

$connectionString = "Host=10.10.10.10:12345;Server=testserver;DatabaseName=testdb;UserID=DBA;Password=123"

[Sap.Data.SQLAnywhere.SAConnection] $conn = New-Object Sap.Data.SQLAnywhere.SAConnection($connectionString)
$conn.Open()

[Sap.Data.SQLAnywhere.SACommand] $command = New-Object Sap.Data.SQLAnywhere.SACommand("UPDATE table SET value = ? WHERE value IS NOT NULL", $conn)

[Sap.Data.SQLAnywhere.SAParameter] $parameter = New-Object Sap.Data.SQLAnywhere.SAParameter
$parameter.SADbType = [Sap.Data.SQLAnywhere.SADbType]::BigInt
$parameter.Value = $myvalue
[void] $command.Parameters.Add($parameter)

try {
    [void] $command.ExecuteNonQuery()
} catch {
    Write-Error $_
}

Exception calling "ExecuteNonQuery" with "0" argument(s): "Unable to cast object of type 'System.Numerics.BigInteger' to type 'System.IConvertible'."