21004847 has 2 divisors, whose sum is σ = 21004848. Its totient is φ = 21004846.

The previous prime is 21004831. The next prime is 21004883. The reversal of 21004847 is 74840012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21004847 - 2⁴ = 21004831 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21004807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502423 + 10502424.

It is an arithmetic number, because the mean of its divisors is an integer number (10502424).

Almost surely, 2^21004847 is an apocalyptic number.

21004847 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004847 is an equidigital number, since it uses as much as digits as its factorization.

21004847 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 21004847 is about 4583.1045155004. The cubic root of 21004847 is about 275.9136422044.

Adding to 21004847 its reverse (74840012), we get a palindrome (95844859).

The spelling of 21004847 in words is "twenty-one million, four thousand, eight hundred forty-seven".