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20688748784 = 2411799771523
BaseRepresentation
bin10011010001001001…
…010100000011110000
31222101211112022221222
4103101021110003300
5314332304430114
613300531404212
71331454314564
oct232111240360
958354468858
1020688748784
1188572941a0
124014753668
131c492a7ab2
1410039716a4
1581146998e
hex4d12540f0

20688748784 has 80 divisors (see below), whose sum is σ = 44356446720. Its totient is φ = 9269345280.

The previous prime is 20688748777. The next prime is 20688748793. The reversal of 20688748784 is 48784788602.

It is a super-2 number, since 2×206887487842 (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13583447 + ... + 13584969.

It is an arithmetic number, because the mean of its divisors is an integer number (554455584).

Almost surely, 220688748784 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20688748784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22178223360).

20688748784 is an abundant number, since it is smaller than the sum of its proper divisors (23667697936).

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

20688748784 is a wasteful number, since it uses less digits than its factorization.

20688748784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2598 (or 2592 counting only the distinct ones).

The product of its (nonzero) digits is 38535168, while the sum is 62.

The spelling of 20688748784 in words is "twenty billion, six hundred eighty-eight million, seven hundred forty-eight thousand, seven hundred eighty-four".

Divisors: 1 2 4 8 11 16 22 44 79 88 158 176 316 632 869 977 1264 1523 1738 1954 3046 3476 3908 6092 6952 7816 10747 12184 13904 15632 16753 21494 24368 33506 42988 67012 77183 85976 120317 134024 154366 171952 240634 268048 308732 481268 617464 849013 962536 1234928 1323487 1487971 1698026 1925072 2646974 2975942 3396052 5293948 5951884 6792104 10587896 11903768 13584208 16367681 21175792 23807536 32735362 65470724 117549709 130941448 235099418 261882896 470198836 940397672 1293046799 1880795344 2586093598 5172187196 10344374392 20688748784