λ
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21,372,820

22 × 5 × 72 × 113 × 193
Abundant Even Composite

21,372,820 factors as 2^2 × 5 × 7^2 × 113 × 193. Its 72 positive divisors give a proper-divisor sum of 31,572,884, so this integer is abundant. The Collatz stopping time is 97 steps.

Prime Factor Structure

Factorization String 2^2 × 5 × 7^2 × 113 × 193
Distinct Prime Factors 5
Square Status No
Abundance Measure Abundant

Analytical Properties

Total Divisors 72
Divisor Sum (σ) 52,945,704
Proper Divisor Sum 31,572,884
Digit Sum / Digital Root 25 (Root: 7)
Adjacent Primes #21372811 ← → #21372839

Radix Representation

Decimal 21372820
Binary 1010001100001111110010100 (25 bits)
Octal 0o121417624
Hexadecimal 0x1461F94

Divisor Catalog (60 of 72)

1 2 4 5 7 10 14 20 28 35 49 70 98 113 140 193 196 226 245 386 452 490 565 772 791 965 980 1,130 1,351 1,582 1,930 2,260 2,702 3,164 3,860 3,955 5,404 5,537 6,755 7,910 9,457 11,074 13,510 15,820 18,914 21,809 22,148 27,020 27,685 37,828 43,618 47,285 55,370 87,236 94,570 109,045 110,740 152,663 189,140 218,090

Collatz Trajectory (97 steps to reach 1)

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

21,372,820 10,686,410 5,343,205 16,029,616 8,014,808 4,007,404 2,003,702 1,001,851 3,005,554 1,502,777 4,508,332 2,254,166 1,127,083 3,381,250 1,690,625 5,071,876 2,535,938 1,267,969 3,803,908 1,901,954 950,977 2,852,932 1,426,466 713,233 2,139,700 1,069,850 534,925 1,604,776 802,388 401,194 200,597 601,792 300,896 150,448 75,224 37,612 18,806 9,403 28,210 14,105 42,316 21,158 10,579 31,738 15,869 47,608 23,804 11,902 5,951 17,854 8,927 26,782 13,391 40,174 20,087 60,262 30,131 90,394 45,197 135,592

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