21452161 has 2 divisors, whose sum is σ = 21452162. Its totient is φ = 21452160.

The previous prime is 21452149. The next prime is 21452191. The reversal of 21452161 is 16125412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19749136 + 1703025 = 4444^2 + 1305^2 .

It is a cyclic number.

It is not a de Polignac number, because 21452161 - 2⁹ = 21451649 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21452111) 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, 10726080 + 10726081.

It is an arithmetic number, because the mean of its divisors is an integer number (10726081).

Almost surely, 2^21452161 is an apocalyptic number.

It is an amenable number.

21452161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21452161 is an equidigital number, since it uses as much as digits as its factorization.

21452161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 480, while the sum is 22.

The square root of 21452161 is about 4631.6477629457. The cubic root of 21452161 is about 277.8584972466.

Adding to 21452161 its reverse (16125412), we get a palindrome (37577573).

The spelling of 21452161 in words is "twenty-one million, four hundred fifty-two thousand, one hundred sixty-one".