21052 has 12 divisors (see below), whose sum is σ = 38920. Its totient is φ = 9936.

The previous prime is 21031. The next prime is 21059. The reversal of 21052 is 25012.

It is an alternating number because its digits alternate between even and odd.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21059) by changing a digit.

21052 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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, 63 + ... + 214.

2²¹⁰⁵² is an apocalyptic number.

It is an amenable number.

21052 is a deficient number, since it is larger than the sum of its proper divisors (17868).

21052 is a wasteful number, since it uses less digits than its factorization.

21052 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300 (or 298 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 21052 is about 145.0930735769. The cubic root of 21052 is about 27.6119950662.

Adding to 21052 its reverse (25012), we get a palindrome (46064).

It can be divided in two parts, 210 and 52, that added together give a palindrome (262).

The spelling of 21052 in words is "twenty-one thousand, fifty-two".