21683 has 2 divisors, whose sum is σ = 21684. Its totient is φ = 21682.

The previous prime is 21673. The next prime is 21701. The reversal of 21683 is 38612.

21683 = T₈₂ + T₈₃ + ... + T₈₇.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21683 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10841 + 10842.

It is an arithmetic number, because the mean of its divisors is an integer number (10842).

2²¹⁶⁸³ is an apocalyptic number.

21683 is a deficient number, since it is larger than the sum of its proper divisors (1).

21683 is an equidigital number, since it uses as much as digits as its factorization.

21683 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 20.

The square root of 21683 is about 147.2514855613. The cubic root of 21683 is about 27.8851588784.

The spelling of 21683 in words is "twenty-one thousand, six hundred eighty-three".