21793 has 8 divisors (see below), whose sum is σ = 24320. Its totient is φ = 19440.

The previous prime is 21787. The next prime is 21799. The reversal of 21793 is 39712.

It is an interprime number because it is at equal distance from previous prime (21787) and next prime (21799).

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21793 is a prime.

It is a plaindrome in base 15.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (21799) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 571 + ... + 607.

It is an arithmetic number, because the mean of its divisors is an integer number (3040).

2²¹⁷⁹³ is an apocalyptic number.

It is an amenable number.

21793 is a deficient number, since it is larger than the sum of its proper divisors (2527).

21793 is a wasteful number, since it uses less digits than its factorization.

21793 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87.

The product of its digits is 378, while the sum is 22.

The square root of 21793 is about 147.6245237080. The cubic root of 21793 is about 27.9322340837.

It can be divided in two parts, 21 and 793, that multiplied together give a triangular number (16653 = T₁₈₂).

The spelling of 21793 in words is "twenty-one thousand, seven hundred ninety-three".