21084313 has 2 divisors, whose sum is σ = 21084314. Its totient is φ = 21084312.

The previous prime is 21084311. The next prime is 21084317. The reversal of 21084313 is 31348012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20720704 + 363609 = 4552^2 + 603^2 .

It is a cyclic number.

It is not a de Polignac number, because 21084313 - 2¹ = 21084311 is a prime.

Together with 21084311, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21084311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10542156 + 10542157.

It is an arithmetic number, because the mean of its divisors is an integer number (10542157).

Almost surely, 2^21084313 is an apocalyptic number.

It is an amenable number.

21084313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21084313 is an equidigital number, since it uses as much as digits as its factorization.

21084313 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21084313 is about 4591.7657823543. The cubic root of 21084313 is about 276.2611518604.

The spelling of 21084313 in words is "twenty-one million, eighty-four thousand, three hundred thirteen".