It is a tau number, because it is divible by the number of its divisors (72).
It is a nialpdrome in base 14.
It is a zygodrome in base 14.
It is an unprimeable number.
17640 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
217640 is an apocalyptic number.
17640 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 17640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33345).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
17640 is a wasteful number, since it uses less digits than its factorization.
17640 is an evil number, because the sum of its binary digits is even.
The square root of 17640 is about 132.8156617271. The cubic root of 17640 is about 26.0315199581.
17640 divided by its product of nonzero digits (168) gives a triangular number (105 = T14).
The spelling of 17640 in words is "seventeen thousand, six hundred forty".