21101317 has 2 divisors, whose sum is σ = 21101318. Its totient is φ = 21101316.

The previous prime is 21101309. The next prime is 21101323. The reversal of 21101317 is 71310112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14945956 + 6155361 = 3866^2 + 2481^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101317 - 2³ = 21101309 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21101317.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550658 + 10550659.

It is an arithmetic number, because the mean of its divisors is an integer number (10550659).

Almost surely, 2^21101317 is an apocalyptic number.

It is an amenable number.

21101317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101317 is an equidigital number, since it uses as much as digits as its factorization.

21101317 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42, while the sum is 16.

The square root of 21101317 is about 4593.6169844688. The cubic root of 21101317 is about 276.3353979341.

Adding to 21101317 its reverse (71310112), we get a palindrome (92411429).

The spelling of 21101317 in words is "twenty-one million, one hundred one thousand, three hundred seventeen".