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Atlas › Integer Profiles › Node 21,361,840

21,361,840

24 × 5 × 257 × 1039
Abundant Even Composite

21,361,840 factors as 2^4 × 5 × 257 × 1039. Its 40 positive divisors give a proper-divisor sum of 28,545,680, so this integer is abundant. The Collatz stopping time is 97 steps.

Prime Factor Structure

Factorization String 2^4 × 5 × 257 × 1039
Distinct Prime Factors 4
Square Status No
Abundance Measure Abundant

Analytical Properties

Total Divisors 40
Divisor Sum (σ) 49,907,520
Proper Divisor Sum 28,545,680
Digit Sum / Digital Root 25 (Root: 7)
Adjacent Primes #21361831 ← → #21361853

Radix Representation

Decimal 21361840
Binary 1010001011111010010110000 (25 bits)
Octal 0o121372260
Hexadecimal 0x145F4B0

Divisor Catalog (40)

1 2 4 5 8 10 16 20 40 80 257 514 1,028 1,039 1,285 2,056 2,078 2,570 4,112 4,156 5,140 5,195 8,312 10,280 10,390 16,624 20,560 20,780 41,560 83,120 267,023 534,046 1,068,092 1,335,115 2,136,184 2,670,230 4,272,368 5,340,460 10,680,920 21,361,840

Collatz Trajectory (97 steps to reach 1)

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

21,361,840 10,680,920 5,340,460 2,670,230 1,335,115 4,005,346 2,002,673 6,008,020 3,004,010 1,502,005 4,506,016 2,253,008 1,126,504 563,252 281,626 140,813 422,440 211,220 105,610 52,805 158,416 79,208 39,604 19,802 9,901 29,704 14,852 7,426 3,713 11,140 5,570 2,785 8,356 4,178 2,089 6,268 3,134 1,567 4,702 2,351 7,054 3,527 10,582 5,291 15,874 7,937 23,812 11,906 5,953 17,860 8,930 4,465 13,396 6,698 3,349 10,048 5,024 2,512 1,256 628

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