toULongOrNull
Parses the string as an ULong number and returns the result or null if the string is not a valid representation of a number.
fun String.toULongOrNull(): ULong?(source)
fun main() {
val valid = "1234567890".toULongOrNull()
println(valid) // prints 1234567890
val invalid = "not_a_number".toULongOrNull()
println(invalid) // prints null
}