21326161 has 2 divisors, whose sum is σ = 21326162. Its totient is φ = 21326160.

The previous prime is 21326131. The next prime is 21326213. The reversal of 21326161 is 16162312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11833600 + 9492561 = 3440^2 + 3081^2 .

It is a cyclic number.

It is not a de Polignac number, because 21326161 - 2¹¹ = 21324113 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21326101) 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, 10663080 + 10663081.

It is an arithmetic number, because the mean of its divisors is an integer number (10663081).

Almost surely, 2^21326161 is an apocalyptic number.

It is an amenable number.

21326161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21326161 is an equidigital number, since it uses as much as digits as its factorization.

21326161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 22.

The square root of 21326161 is about 4618.0256603878. The cubic root of 21326161 is about 277.3134248928.

Adding to 21326161 its reverse (16162312), we get a palindrome (37488473).

The spelling of 21326161 in words is "twenty-one million, three hundred twenty-six thousand, one hundred sixty-one".