21126 has 16 divisors (see below), whose sum is σ = 48384. Its totient is φ = 6024.

The previous prime is 21121. The next prime is 21139. The reversal of 21126 is 62112.

21126 = T₂₄ + T₂₅ + ... + T₅₁.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 21126.

It is not an unprimeable number, because it can be changed into a prime (21121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 210 + ... + 293.

It is an arithmetic number, because the mean of its divisors is an integer number (3024).

2²¹¹²⁶ is an apocalyptic number.

21126 is an abundant number, since it is smaller than the sum of its proper divisors (27258).

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 (24192).

21126 is a wasteful number, since it uses less digits than its factorization.

21126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515.

The product of its digits is 24, while the sum is 12.

The square root of 21126 is about 145.3478586014. The cubic root of 21126 is about 27.6443102568.

Adding to 21126 its reverse (62112), we get a palindrome (83238).

It can be divided in two parts, 2 and 1126, that added together give a triangular number (1128 = T₄₇).

The spelling of 21126 in words is "twenty-one thousand, one hundred twenty-six".