21084847 has 6 divisors (see below), whose sum is σ = 24527328. Its totient is φ = 18072684.

The previous prime is 21084839. The next prime is 21084853. The reversal of 21084847 is 74848012.

It is not a de Polignac number, because 21084847 - 2³ = 21084839 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21084887) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215103 + ... + 215200.

It is an arithmetic number, because the mean of its divisors is an integer number (4087888).

Almost surely, 2^21084847 is an apocalyptic number.

21084847 is a deficient number, since it is larger than the sum of its proper divisors (3442481).

21084847 is an equidigital number, since it uses as much as digits as its factorization.

21084847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430317 (or 430310 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 34.

The square root of 21084847 is about 4591.8239295513. The cubic root of 21084847 is about 276.2634841189.

The spelling of 21084847 in words is "twenty-one million, eighty-four thousand, eight hundred forty-seven".