21096 has 24 divisors (see below), whose sum is σ = 57330. Its totient is φ = 7008.

The previous prime is 21089. The next prime is 21101. The reversal of 21096 is 69012.

It can be written as a sum of positive squares in only one way, i.e., 12996 + 8100 = 114^2 + 90^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (18).

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

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 75 + ... + 218.

2²¹⁰⁹⁶ is an apocalyptic number.

It is an amenable number.

21096 is an abundant number, since it is smaller than the sum of its proper divisors (36234).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21096 is a wasteful number, since it uses less digits than its factorization.

21096 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305 (or 298 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 21096 is about 145.2446212429. The cubic root of 21096 is about 27.6312186133.

The spelling of 21096 in words is "twenty-one thousand, ninety-six".