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18969720 = 23357112053
BaseRepresentation
bin100100001011…
…1010001111000
31022200202120020
41020113101320
514324012340
61514330440
7320145210
oct110272170
938622506
1018969720
11a787260
126429a20
133c124b3
14273b240
1519ea9d0
hex1217478

18969720 has 128 divisors (see below), whose sum is σ = 70986240. Its totient is φ = 3939840.

The previous prime is 18969701. The next prime is 18969767. The reversal of 18969720 is 2796981.

18969720 is a nontrivial binomial coefficient, being equal to C(6160, 2).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8214 + ... + 10266.

It is an arithmetic number, because the mean of its divisors is an integer number (554580).

Almost surely, 218969720 is an apocalyptic number.

18969720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18969720 is the 6159-th triangular number and also the 3080-th hexagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18969720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35493120).

18969720 is an abundant number, since it is smaller than the sum of its proper divisors (52016520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18969720 is a wasteful number, since it uses less digits than its factorization.

18969720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2085 (or 2081 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 18969720 is about 4355.4242043686. The cubic root of 18969720 is about 266.6983365165.

The spelling of 18969720 in words is "eighteen million, nine hundred sixty-nine thousand, seven hundred twenty".

Divisors: 1 2 3 4 5 6 7 8 10 11 12 14 15 20 21 22 24 28 30 33 35 40 42 44 55 56 60 66 70 77 84 88 105 110 120 132 140 154 165 168 210 220 231 264 280 308 330 385 420 440 462 616 660 770 840 924 1155 1320 1540 1848 2053 2310 3080 4106 4620 6159 8212 9240 10265 12318 14371 16424 20530 22583 24636 28742 30795 41060 43113 45166 49272 57484 61590 67749 71855 82120 86226 90332 112915 114968 123180 135498 143710 158081 172452 180664 215565 225830 246360 270996 287420 316162 338745 344904 431130 451660 474243 541992 574840 632324 677490 790405 862260 903320 948486 1264648 1354980 1580810 1724520 1896972 2371215 2709960 3161620 3793944 4742430 6323240 9484860 18969720