20000 has 30 divisors (see below), whose sum is σ = 49203.
Its totient is φ = 8000.
The previous prime is 19997. The next prime is 20011. The reversal of 20000 is 2.
It is a powerful number, because all its prime factors have an exponent greater than 1
and also an Achilles number because it is not a perfect power.
20000 is nontrivially palindromic in base 7 and base 15.
It can be written as a sum of positive squares in 3 ways, for example, as 4624 + 15376 = 68^2 + 124^2
It is a sliding number, since 20000 = 10000 + 10000 and 1/10000 + 1/10000 = 0.00020000.
It is an ABA number since it can be written as A⋅BA, here for A=2, B=100.
It is a Harshad number since it is a multiple of its sum of digits (2).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
It is a Duffinian number.
It is a nialpdrome in base 10.
It is a zygodrome in base 7.
It is an unprimeable number.
It is a pernicious number, because its binary representation contains a prime number (5) of ones.
It is a polite number, since it can be written in 4 ways as a sum of consecutive naturals, for example, 3998 + ... + 4002.
220000 is an apocalyptic number.
20000 is a gapful number since it is divisible by the number (20) 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 20000
20000 is an abundant number, since it is smaller than the sum of its proper divisors (29203).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
20000 is an frugal number, since it uses more digits than its factorization.
20000 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 30 (or 7 counting only the distinct ones).
The product of its (nonzero) digits is 2, while the sum is 2.
The square root of 20000 is about 141.4213562373.
The cubic root of 20000 is about 27.1441761659.
The spelling of 20000 in words is "twenty thousand", and is thus an iban number.