21317683 has 2 divisors, whose sum is σ = 21317684. Its totient is φ = 21317682.

The previous prime is 21317669. The next prime is 21317689. The reversal of 21317683 is 38671312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21317683 - 2⁵ = 21317651 is a prime.

It is not a weakly prime, because it can be changed into another prime (21317689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658841 + 10658842.

It is an arithmetic number, because the mean of its divisors is an integer number (10658842).

Almost surely, 2^21317683 is an apocalyptic number.

21317683 is a deficient number, since it is larger than the sum of its proper divisors (1).

21317683 is an equidigital number, since it uses as much as digits as its factorization.

21317683 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 31.

The square root of 21317683 is about 4617.1076444025. The cubic root of 21317683 is about 277.2766723047.

Adding to 21317683 its reverse (38671312), we get a palindrome (59988995).

The spelling of 21317683 in words is "twenty-one million, three hundred seventeen thousand, six hundred eighty-three".