21068 has 12 divisors (see below), whose sum is σ = 38640. Its totient is φ = 10032.

The previous prime is 21067. The next prime is 21089. The reversal of 21068 is 86012.

It is not an unprimeable number, because it can be changed into a prime (21061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23 + ... + 206.

It is an arithmetic number, because the mean of its divisors is an integer number (3220).

2²¹⁰⁶⁸ is an apocalyptic number.

It is an amenable number.

21068 is a deficient number, since it is larger than the sum of its proper divisors (17572).

21068 is a wasteful number, since it uses less digits than its factorization.

21068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256 (or 254 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21068 is about 145.1482001266. The cubic root of 21068 is about 27.6189885434.

The spelling of 21068 in words is "twenty-one thousand, sixty-eight".