21163361 has 2 divisors, whose sum is σ = 21163362. Its totient is φ = 21163360.

The previous prime is 21163343. The next prime is 21163403. The reversal of 21163361 is 16336112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12496225 + 8667136 = 3535^2 + 2944^2 .

It is a cyclic number.

It is not a de Polignac number, because 21163361 - 2¹⁴ = 21146977 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21163061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10581680 + 10581681.

It is an arithmetic number, because the mean of its divisors is an integer number (10581681).

Almost surely, 2^21163361 is an apocalyptic number.

It is an amenable number.

21163361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21163361 is an equidigital number, since it uses as much as digits as its factorization.

21163361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 23.

The square root of 21163361 is about 4600.3653115812. The cubic root of 21163361 is about 276.6059683620.

Adding to 21163361 its reverse (16336112), we get a palindrome (37499473).

The spelling of 21163361 in words is "twenty-one million, one hundred sixty-three thousand, three hundred sixty-one".