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18424 = 237247
BaseRepresentation
bin100011111111000
3221021101
410133320
51042144
6221144
7104500
oct43770
927241
1018424
111292a
12a7b4
138503
146a00
1556d4
hex47f8

18424 has 24 divisors (see below), whose sum is σ = 41040. Its totient is φ = 7728.

The previous prime is 18413. The next prime is 18427. The reversal of 18424 is 42481.

18424 = T1 + T2 + ... + T47.

18424 is a nontrivial binomial coefficient, being equal to C(49, 3).

It is a nude number because it is divisible by every one of its digits.

It is a zygodrome in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18427) by changing a digit.

It is the 47-th tetrahedral number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 369 + ... + 415.

It is an arithmetic number, because the mean of its divisors is an integer number (1710).

218424 is an apocalyptic number.

18424 is a gapful number since it is divisible by the number (14) 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 18424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20520).

18424 is an abundant number, since it is smaller than the sum of its proper divisors (22616).

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

18424 is a wasteful number, since it uses less digits than its factorization.

18424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67 (or 56 counting only the distinct ones).

The product of its digits is 256, while the sum is 19.

The square root of 18424 is about 135.7350360077. The cubic root of 18424 is about 26.4115957631.

The spelling of 18424 in words is "eighteen thousand, four hundred twenty-four".

Divisors: 1 2 4 7 8 14 28 47 49 56 94 98 188 196 329 376 392 658 1316 2303 2632 4606 9212 18424