20810 has 8 divisors (see below), whose sum is σ = 37476.
Its totient is φ = 8320.
The previous prime is 20809. The next prime is 20849. The reversal of 20810 is 1802.
20810 = T45 + T46 + ... +
20810 = 362 + 372 + ... + 472.
It can be written as a sum of positive squares in 2 ways, for example, as 20449 + 361 = 143^2 + 19^2
It is a sphenic number, since it is the product of 3 distinct primes.
It is a super-2 number, since 2×208102 = 866112200, which contains 22 as substring.
It is a Curzon number.
It is a plaindrome in base 7.
It is a junction number, because it is equal to n+sod(n) for n = 20791 and 20800.
It is a congruent number.
It is an unprimeable number.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1031 + ... + 1050.
220810 is an apocalyptic number.
20810 is a deficient number, since it is larger than the sum of its proper divisors (16666).
20810 is a wasteful number, since it uses less digits than its factorization.
20810 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 2088.
The product of its (nonzero) digits is 16, while the sum is 11.
The square root of 20810 is about 144.2567156149.
The cubic root of 20810 is about 27.5057839074.
The spelling of 20810 in words is "twenty thousand, eight hundred ten".