21301361 has 2 divisors, whose sum is σ = 21301362. Its totient is φ = 21301360.

The previous prime is 21301339. The next prime is 21301363. The reversal of 21301361 is 16310312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21298225 + 3136 = 4615^2 + 56^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21301361 is a prime.

Together with 21301363, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21301363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650680 + 10650681.

It is an arithmetic number, because the mean of its divisors is an integer number (10650681).

Almost surely, 2^21301361 is an apocalyptic number.

It is an amenable number.

21301361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21301361 is an equidigital number, since it uses as much as digits as its factorization.

21301361 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 21301361 is about 4615.3397491409. The cubic root of 21301361 is about 277.2058881051.

Adding to 21301361 its reverse (16310312), we get a palindrome (37611673).

The spelling of 21301361 in words is "twenty-one million, three hundred one thousand, three hundred sixty-one".