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18787940 = 2252921117
BaseRepresentation
bin100011110101…
…0111001100100
31022100112012122
41013222321210
514302203230
61510405112
7315460223
oct107527144
938315178
1018787940
11a672726
126360798
133b7a832
1426d0cba
1519b1be5
hex11eae64

18787940 has 36 divisors (see below), whose sum is σ = 40898676. Its totient is φ = 7249536.

The previous prime is 18787927. The next prime is 18787943. The reversal of 18787940 is 4978781.

It can be written as a sum of positive squares in 6 ways, for example, as 2010724 + 16777216 = 1418^2 + 4096^2 .

It is a junction number, because it is equal to n+sod(n) for n = 18787891 and 18787900.

It is not an unprimeable number, because it can be changed into a prime (18787943) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 16262 + ... + 17378.

Almost surely, 218787940 is an apocalyptic number.

18787940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18787940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20449338).

18787940 is an abundant number, since it is smaller than the sum of its proper divisors (22110736).

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

18787940 is a wasteful number, since it uses less digits than its factorization.

18787940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1184 (or 1153 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 18787940 is about 4334.5057388357. The cubic root of 18787940 is about 265.8437094205.

The spelling of 18787940 in words is "eighteen million, seven hundred eighty-seven thousand, nine hundred forty".

Divisors: 1 2 4 5 10 20 29 58 116 145 290 580 841 1117 1682 2234 3364 4205 4468 5585 8410 11170 16820 22340 32393 64786 129572 161965 323930 647860 939397 1878794 3757588 4696985 9393970 18787940