MSISDN
The diallable phone number in international E.164 format, which identifies a subscription and can move to another network.
Definitions only — a term explained here is not a service we sell.
The MSISDN is the diallable phone number in international format: a country code of one to three digits followed by the national significant number, up to 15 digits in total under ITU-T E.164. It identifies the subscription for routing and billing, and it can move between operators.
The IMSI is a separate identifier
- MCC 274
- MNC 01
- MSIN 1234567890
Text description
The figure shows an IMSI, not an MSISDN. MCC names the country, MNC names the network and MSIN names the subscriber; the network maps the diallable MSISDN to that subscription.
Format and normalization
Before sending, normalize the number: strip spaces, dashes and brackets, turn a leading 00 into +, drop the national trunk prefix, and store the result as E.164, keeping the original input for audit. A number that fails validation is not necessarily invalid, because short codes, extensions and service numbers fall outside E.164. Deduplicate on the normalized number, and do not infer the operator from the prefix; use portability data. The Four numbers explainer covers the MSISDN, IMSI, ICCID and IMEI.