20920 has 16 divisors (see below), whose sum is σ = 47160.
Its totient is φ = 8352.
The previous prime is 20903. The next prime is 20921. The reversal of 20920 is 2902.
It is a plaindrome in base 11.
It is a self number, because there is not a number n which added to its sum of digits gives 20920.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20921) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 222 + ... + 301.
220920 is an apocalyptic number.
20920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.
It is an amenable number.
20920 is an abundant number, since it is smaller than the sum of its proper divisors (26240).
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 (23580).
20920 is a wasteful number, since it uses less digits than its factorization.
20920 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 534 (or 530 counting only the distinct ones).
The product of its (nonzero) digits is 36, while the sum is 13.
The square root of 20920 is about 144.6374778541.
The cubic root of 20920 is about 27.5541632241.
The spelling of 20920 in words is "twenty thousand, nine hundred twenty".