21106361 has 2 divisors, whose sum is σ = 21106362. Its totient is φ = 21106360.

The previous prime is 21106343. The next prime is 21106369. The reversal of 21106361 is 16360112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19749136 + 1357225 = 4444^2 + 1165^2 .

It is a cyclic number.

It is not a de Polignac number, because 21106361 - 2¹⁸ = 20844217 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21106369) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10553180 + 10553181.

It is an arithmetic number, because the mean of its divisors is an integer number (10553181).

Almost surely, 2^21106361 is an apocalyptic number.

It is an amenable number.

21106361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21106361 is an equidigital number, since it uses as much as digits as its factorization.

21106361 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21106361 is about 4594.1659743636. The cubic root of 21106361 is about 276.3574143277.

Adding to 21106361 its reverse (16360112), we get a palindrome (37466473).

The spelling of 21106361 in words is "twenty-one million, one hundred six thousand, three hundred sixty-one".