10921 has 4 divisors (see below), whose sum is σ = 11152. Its totient is φ = 10692.

The previous prime is 10909. The next prime is 10937. The reversal of 10921 is 12901.

10921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 10921 - 2⁵ = 10889 is a prime.

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

It is the 105-th Hogben number.

It is a Duffinian number.

10921 is a lucky number.

It is a nialpdrome in base 4.

It is a zygodrome in base 3.

It is not an unprimeable number, because it can be changed into a prime (10321) by changing a digit.

It is a nontrivial repunit in base 104.

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, 15 + ... + 148.

It is an arithmetic number, because the mean of its divisors is an integer number (2788).

2¹⁰⁹²¹ is an apocalyptic number.

It is an amenable number.

10921 is a deficient number, since it is larger than the sum of its proper divisors (231).

10921 is an equidigital number, since it uses as much as digits as its factorization.

10921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230.

The product of its (nonzero) digits is 18, while the sum is 13.

The square root of 10921 is about 104.5035884551. The cubic root of 10921 is about 22.1864322041.

The spelling of 10921 in words is "ten thousand, nine hundred twenty-one".