21445147 has 2 divisors, whose sum is σ = 21445148. Its totient is φ = 21445146.

The previous prime is 21445141. The next prime is 21445157. The reversal of 21445147 is 74154412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21445147 - 2¹¹ = 21443099 is a prime.

It is not a weakly prime, because it can be changed into another prime (21445141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10722573 + 10722574.

It is an arithmetic number, because the mean of its divisors is an integer number (10722574).

Almost surely, 2^21445147 is an apocalyptic number.

21445147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21445147 is an equidigital number, since it uses as much as digits as its factorization.

21445147 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4480, while the sum is 28.

The square root of 21445147 is about 4630.8905191118. The cubic root of 21445147 is about 277.8282110680.

Adding to 21445147 its reverse (74154412), we get a palindrome (95599559).

The spelling of 21445147 in words is "twenty-one million, four hundred forty-five thousand, one hundred forty-seven".