19808 has 12 divisors (see below), whose sum is σ = 39060. Its totient is φ = 9888.
The previous prime is 19801. The next prime is 19813. The reversal of 19808 is 80891.
It is a Smith number, since the sum of its digits (26) coincides with the sum of the digits of its prime factors.
It is an Ulam number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (19801) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 278 + ... + 341.
It is an arithmetic number, because the mean of its divisors is an integer number (3255).
219808 is an apocalyptic number.
It is an amenable number.
19808 is a deficient number, since it is larger than the sum of its proper divisors (19252).
19808 is an equidigital number, since it uses as much as digits as its factorization.
19808 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 629 (or 621 counting only the distinct ones).
The product of its (nonzero) digits is 576, while the sum is 26.
The square root of 19808 is about 140.7408966861. The cubic root of 19808 is about 27.0570353539.
The spelling of 19808 in words is "nineteen thousand, eight hundred eight".
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