65

65 is the natural number that comes after 64 and before 66. It is an odd, composite integer. Its prime factorization is 5 × 13, and its positive divisors are 1, 5, 13, and 65.

In various numeral systems, 65 is written as 65 in decimal, 0x41 in hexadecimal, 101 in octal, and 1000001 in binary. In Roman numerals it is LXV. The ASCII and Unicode code point for the uppercase letter A is 65 (U+0041).

65 also appears in real-world contexts. It is the international calling code for Singapore. The element with atomic number 65 is terbium (Tb), a lanthanide used in phosphors and various alloys. In geometry, a regular 65-gon has interior angles of (63 × 180) / 65 ≈ 174.46 degrees.