17920 has 40 divisors (see below), whose sum is σ = 49104. Its totient is φ = 6144.
The previous prime is 17911. The next prime is 17921. The reversal of 17920 is 2971.
It is a tau number, because it is divible by the number of its divisors (40).
It is a super-2 number, since 2×179202 = 642252800, which contains 22 as substring.
It is a nialpdrome in base 8.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (17921) by changing a digit.
17920 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
It is a pernicious number, because its binary representation contains a prime number (3) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2557 + ... + 2563.
17920 is a Friedman number, since it can be written as 70*2^(9-1), using all its digits and the basic arithmetic operations.
217920 is an apocalyptic number.
17920 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 17920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24552).
17920 is an abundant number, since it is smaller than the sum of its proper divisors (31184).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
17920 is an frugal number, since it uses more digits than its factorization.
17920 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 30 (or 14 counting only the distinct ones).
The product of its (nonzero) digits is 126, while the sum is 19.
The square root of 17920 is about 133.8656042455. The cubic root of 17920 is about 26.1685304815.
It can be divided in two parts, 1 and 7920, that added together give a square (7921 = 892).
The spelling of 17920 in words is "seventeen thousand, nine hundred twenty".
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