/** ******************************
 * Netherlands mobile phone number *
 *********************************/
/**
 * Mobile numbers start with 06
 * Format: 0A BBB BBBB (9 digits with leading 0 in local format)
 * Reference: https://en.wikipedia.org/wiki/Telephone_numbers_in_the_Netherlands
 */
export declare function is_nl_mobile_phone_prefix(tel: string): boolean;
/**
 * with/without +31 prefix
 */
export declare function is_nl_mobile_phone(tel: number | string): boolean;
/**
 * very forgiving
 *
 * @returns +31xxxxxxxxx if valid (9 digits after country code, NO leading 0 in internal format)
 *          empty string if not valid
 *
 * Format notes:
 * - Local format: 06 12345678 (9 digits WITH leading 0) - used in Netherlands
 * - Internal format: +31 6 12345678 (9 digits after +31, NO leading 0) - always 9 digits
 * - Display format: +31 6 12345678 (formatted by format_nl_mobile_phone)
 */
export declare function to_full_nl_mobile_phone(tel: string | number): string;
/**
 * @returns +31 6 xxxx xxxx if valid
 */
export declare function format_nl_mobile_phone(tel: string | number): string;