21824161 has 2 divisors, whose sum is σ = 21824162. Its totient is φ = 21824160.

The previous prime is 21824149. The next prime is 21824167. The reversal of 21824161 is 16142812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19633761 + 2190400 = 4431^2 + 1480^2 .

It is a cyclic number.

It is not a de Polignac number, because 21824161 - 2⁵ = 21824129 is a prime.

It is not a weakly prime, because it can be changed into another prime (21824167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10912080 + 10912081.

It is an arithmetic number, because the mean of its divisors is an integer number (10912081).

Almost surely, 2^21824161 is an apocalyptic number.

It is an amenable number.

21824161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21824161 is an equidigital number, since it uses as much as digits as its factorization.

21824161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 768, while the sum is 25.

The square root of 21824161 is about 4671.6336543012. The cubic root of 21824161 is about 279.4554083088.

Adding to 21824161 its reverse (16142812), we get a palindrome (37966973).

The spelling of 21824161 in words is "twenty-one million, eight hundred twenty-four thousand, one hundred sixty-one".