084

084 is a string of digits that can denote the decimal number 84 when written with a leading zero. As a number, 84 is even and composite: its prime factorization is 2^2 × 3 × 7, and it has 12 positive divisors. It is an abundant number since the sum of its proper divisors (1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42) equals 140, which exceeds 84. In various bases it is represented as binary 1010100, decimal 84, hexadecimal 0x54, and octal 124. It is also a Harshad (Niven) number in base 10 because 84 is divisible by the sum of its digits (8+4 = 12).

In science, the element with atomic number 84 is polonium (Po). Polonium is a highly radioactive metal discovered by Marie and Pierre Curie in 1898 and named after Poland. It has several isotopes; Po-210 is among the best known and has been used in heat sources for specialized devices and, historically, as a poison in high-profile incidents.

In computing and coding, the decimal value 84 corresponds to the ASCII character 'T'. It can be represented in different bases as 0x54 in hexadecimal and 124 in octal, illustrating how the same value appears across numeral systems.

In telecommunications, 084 is a prefix used for non-geographic service numbers in the United Kingdom, often appearing in numbers such as 0844 or 0845. Such numbers are typically used by businesses and may incur higher call charges, depending on the service and dialing plan.