21443447 has 2 divisors, whose sum is σ = 21443448. Its totient is φ = 21443446.

The previous prime is 21443437. The next prime is 21443449. The reversal of 21443447 is 74434412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21443447 - 2⁴ = 21443431 is a prime.

Together with 21443449, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21443449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721723 + 10721724.

It is an arithmetic number, because the mean of its divisors is an integer number (10721724).

Almost surely, 2^21443447 is an apocalyptic number.

21443447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21443447 is an equidigital number, since it uses as much as digits as its factorization.

21443447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 29.

The square root of 21443447 is about 4630.7069654643. The cubic root of 21443447 is about 277.8208695400.

Adding to 21443447 its reverse (74434412), we get a palindrome (95877859).

The spelling of 21443447 in words is "twenty-one million, four hundred forty-three thousand, four hundred forty-seven".