11921 has 8 divisors (see below), whose sum is σ = 14784. Its totient is φ = 9360.

The previous prime is 11909. The next prime is 11923. The reversal of 11921 is 12911.

11921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a de Polignac number, because none of the positive numbers 2^k-11921 is a prime.

It is a super-2 number, since 2×11921² = 284220482, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 11896 and 11905.

It is not an unprimeable number, because it can be changed into a prime (11923) 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 7 ways as a sum of consecutive naturals, for example, 26 + ... + 156.

It is an arithmetic number, because the mean of its divisors is an integer number (1848).

2¹¹⁹²¹ is an apocalyptic number.

It is an amenable number.

11921 is a deficient number, since it is larger than the sum of its proper divisors (2863).

11921 is a wasteful number, since it uses less digits than its factorization.

11921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151.

The product of its digits is 18, while the sum is 14.

The square root of 11921 is about 109.1833320613. The cubic root of 11921 is about 22.8439339605.

Adding to 11921 its sum of digits (14), we get a triangular number (11935 = T₁₅₄).

Subtracting 11921 from its reverse (12911), we obtain a triangular number (990 = T₄₄).

The spelling of 11921 in words is "eleven thousand, nine hundred twenty-one".