21432241 has 2 divisors, whose sum is σ = 21432242. Its totient is φ = 21432240.

The previous prime is 21432239. The next prime is 21432259. The reversal of 21432241 is 14223412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21390625 + 41616 = 4625^2 + 204^2 .

It is a cyclic number.

It is not a de Polignac number, because 21432241 - 2¹ = 21432239 is a prime.

Together with 21432239, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21432211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716120 + 10716121.

It is an arithmetic number, because the mean of its divisors is an integer number (10716121).

Almost surely, 2^21432241 is an apocalyptic number.

It is an amenable number.

21432241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21432241 is an equidigital number, since it uses as much as digits as its factorization.

21432241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 19.

The square root of 21432241 is about 4629.4968409105. The cubic root of 21432241 is about 277.7724662036.

Adding to 21432241 its reverse (14223412), we get a palindrome (35655653).

The spelling of 21432241 in words is "twenty-one million, four hundred thirty-two thousand, two hundred forty-one".