19540 has 12 divisors (see below), whose sum is σ = 41076.
Its totient is φ = 7808.
The previous prime is 19531. The next prime is 19541. The reversal of 19540 is 4591.
It can be written as a sum of positive squares in 2 ways, for example, as 13456 + 6084 = 116^2 + 78^2
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (19541) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 469 + ... + 508.
It is an arithmetic number, because the mean of its divisors is an integer number (3423).
219540 is an apocalyptic number.
19540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.
It is an amenable number.
19540 is an abundant number, since it is smaller than the sum of its proper divisors (21536).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20538).
19540 is a wasteful number, since it uses less digits than its factorization.
19540 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 986 (or 984 counting only the distinct ones).
The product of its (nonzero) digits is 180, while the sum is 19.
The square root of 19540 is about 139.7855500401.
The cubic root of 19540 is about 26.9344546364.
The spelling of 19540 in words is "nineteen thousand, five hundred forty".