21683659 has 2 divisors, whose sum is σ = 21683660. Its totient is φ = 21683658.

The previous prime is 21683611. The next prime is 21683699. The reversal of 21683659 is 95638612.

It is an a-pointer prime, because the next prime (21683699) can be obtained adding 21683659 to its sum of digits (40).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21683659 - 2⁷ = 21683531 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21683699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10841829 + 10841830.

It is an arithmetic number, because the mean of its divisors is an integer number (10841830).

Almost surely, 2^21683659 is an apocalyptic number.

21683659 is a deficient number, since it is larger than the sum of its proper divisors (1).

21683659 is an equidigital number, since it uses as much as digits as its factorization.

21683659 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 40.

The square root of 21683659 is about 4656.5715929211. The cubic root of 21683659 is about 278.8544137518.

The spelling of 21683659 in words is "twenty-one million, six hundred eighty-three thousand, six hundred fifty-nine".