1,216,638

2 × 3² × 257 × 263

Starting at 1,216,638, the Collatz iteration reaches 1 after 85 steps. The first transition is 608319; the starting value is even with 24 positive divisors.

Prime Factor Structure

Factorization String 2 × 3^2 × 257 × 263

Distinct Prime Factors 4

Square Status No

Abundance Measure Abundant

Analytical Properties

Total Divisors 24

Divisor Sum (σ) 2,656,368

Proper Divisor Sum 1,439,730

Digit Sum / Digital Root 27 (Root: 9)

Adjacent Primes #1216619 ← → #1216681

Radix Representation

Decimal	1216638
Binary	100101001000001111110 (21 bits)
Octal	0o4510176
Hexadecimal	0x12907E

Divisor Catalog (24)

1 2 3 6 9 18 257 263 514 526 771 789 1,542 1,578 2,313 2,367 4,626 4,734 67,591 135,182 202,773 405,546 608,319 1,216,638

Collatz Trajectory (85 steps to reach 1)

Iterative sequence n → n/2 (if even) or 3n+1 (if odd):

1,216,638 608,319 1,824,958 912,479 2,737,438 1,368,719 4,106,158 2,053,079 6,159,238 3,079,619 9,238,858 4,619,429 13,858,288 6,929,144 3,464,572 1,732,286 866,143 2,598,430 1,299,215 3,897,646 1,948,823 5,846,470 2,923,235 8,769,706 4,384,853 13,154,560 6,577,280 3,288,640 1,644,320 822,160 411,080 205,540 102,770 51,385 154,156 77,078 38,539 115,618 57,809 173,428 86,714 43,357 130,072 65,036 32,518 16,259 48,778 24,389 73,168 36,584 18,292 9,146 4,573 13,720 6,860 3,430 1,715 5,146 2,573 7,720

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