253 (number)

← 252 253 254 →
← 200 210 220 230 240 250 260 270 280 290 → List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	two hundred fifty-three
Ordinal	253rd (two hundred and fifty-third)
Factorization	11 × 23
Divisors	1, 11, 23, 253
Roman numeral	CCLIII
Binary	111111012
Ternary	1001013
Quaternary	33314
Quinary	20035
Senary	11016
Octal	3758
Duodecimal	19112
Hexadecimal	FD16
Vigesimal	CD20
Base 36	7136

253 (two hundred [and] fifty-three) is the natural number following 252 and preceding 254.

In mathematics

253 is:

• a semiprime since it is the product of 2 primes.
• a triangular number.^[1]
• a star number.^[2]
• a centered heptagonal number.^[3]
• a centered nonagonal number.^[4]
• a Blum integer.^[5]
• a member of the 13-aliquot tree.

References

1. "Sloane's A000217 : triangular numbers", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
2. "Sloane's A003154 : Centered 12-gonal numbers. Also star numbers: 6*n*(n-1) + 1", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
3. "Sloane's A069099 : Centered heptagonal numbers. a(n) = (7*n^2 - 7*n + 2)/2", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
4. "Sloane's A060544 : Centered 9-gonal numbers. (3n-1)*(3n-2)/2", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
5. "Sloane's A016105 : Blum integers: numbers of the form p * q where p and q are distinct primes congruent to 3 (mod 4)", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.