20550 has 24 divisors (see below), whose sum is σ = 51336. Its totient is φ = 5440.

The previous prime is 20549. The next prime is 20551. The reversal of 20550 is 5502.

It is an interprime number because it is at equal distance from previous prime (20549) and next prime (20551).

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20551) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 82 + ... + 218.

It is an arithmetic number, because the mean of its divisors is an integer number (2139).

2²⁰⁵⁵⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25668).

20550 is an abundant number, since it is smaller than the sum of its proper divisors (30786).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20550 is a wasteful number, since it uses less digits than its factorization.

20550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152 (or 147 counting only the distinct ones).

The product of its (nonzero) digits is 50, while the sum is 12.

The square root of 20550 is about 143.3527118683. The cubic root of 20550 is about 27.3907511363.

The spelling of 20550 in words is "twenty thousand, five hundred fifty".