18,421,991

7² × 397 × 947

18,421,991 factors as 7^2 × 397 × 947. Its 12 positive divisors give a proper-divisor sum of 3,084,337, so this integer is deficient. The Collatz stopping time is 107 steps.

Prime Factor Structure

Factorization String 7^2 × 397 × 947

Distinct Prime Factors 3

Square Status No

Abundance Measure Deficient

Analytical Properties

Total Divisors 12

Divisor Sum (σ) 21,506,328

Proper Divisor Sum 3,084,337

Digit Sum / Digital Root 35 (Root: 8)

Adjacent Primes #18421987 ← → #18421993

Radix Representation

Decimal	18421991
Binary	1000110010001100011100111 (25 bits)
Octal	0o106214347
Hexadecimal	0x11918E7

Divisor Catalog (12)

1 7 49 397 947 2,779 6,629 19,453 46,403 375,959 2,631,713 18,421,991

Collatz Trajectory (107 steps to reach 1)

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

18,421,991 55,265,974 27,632,987 82,898,962 41,449,481 124,348,444 62,174,222 31,087,111 93,261,334 46,630,667 139,892,002 69,946,001 209,838,004 104,919,002 52,459,501 157,378,504 78,689,252 39,344,626 19,672,313 59,016,940 29,508,470 14,754,235 44,262,706 22,131,353 66,394,060 33,197,030 16,598,515 49,795,546 24,897,773 74,693,320 37,346,660 18,673,330 9,336,665 28,009,996 14,004,998 7,002,499 21,007,498 10,503,749 31,511,248 15,755,624 7,877,812 3,938,906 1,969,453 5,908,360 2,954,180 1,477,090 738,545 2,215,636 1,107,818 553,909 1,661,728 830,864 415,432 207,716 103,858 51,929 155,788 77,894 38,947 116,842

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