21150 has 36 divisors (see below), whose sum is σ = 58032. Its totient is φ = 5520.

The previous prime is 21149. The next prime is 21157. The reversal of 21150 is 5112.

21150 = T₂₈ + T₂₉ + ... + T₅₂.

It is a happy number.

21150 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (9).

21150 is strictly pandigital in base 6.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21157) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 427 + ... + 473.

It is an arithmetic number, because the mean of its divisors is an integer number (1612).

2²¹¹⁵⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21150, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29016).

21150 is an abundant number, since it is smaller than the sum of its proper divisors (36882).

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

21150 is a wasteful number, since it uses less digits than its factorization.

21150 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65 (or 57 counting only the distinct ones).

The product of its (nonzero) digits is 10, while the sum is 9.

The square root of 21150 is about 145.4303957225. The cubic root of 21150 is about 27.6547746508.

Adding to 21150 its reverse (5112), we get a palindrome (26262).

It can be divided in two parts, 21 and 150, that added together give a palindrome (171).

The spelling of 21150 in words is "twenty-one thousand, one hundred fifty".