21022 has 8 divisors (see below), whose sum is σ = 32976. Its totient is φ = 10032.

The previous prime is 21019. The next prime is 21023. The reversal of 21022 is 22012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a nialpdrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 20996 and 21014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023) 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, 183 + ... + 274.

It is an arithmetic number, because the mean of its divisors is an integer number (4122).

2²¹⁰²² is an apocalyptic number.

21022 is the 92-nd heptagonal number.

21022 is the 78-th centered heptagonal number.

21022 is a deficient number, since it is larger than the sum of its proper divisors (11954).

21022 is a wasteful number, since it uses less digits than its factorization.

21022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 482.

The product of its (nonzero) digits is 8, while the sum is 7.

The square root of 21022 is about 144.9896548034. The cubic root of 21022 is about 27.5988727398.

Adding to 21022 its reverse (22012), we get a palindrome (43034).

Subtracting 21022 from its reverse (22012), we obtain a triangular number (990 = T₄₄).

It can be divided in two parts, 210 and 22, that added together give a palindrome (232).

The spelling of 21022 in words is "twenty-one thousand, twenty-two", and thus it is an iban number.