21010013 has 2 divisors, whose sum is σ = 21010014. Its totient is φ = 21010012.

The previous prime is 21009997. The next prime is 21010037. The reversal of 21010013 is 31001012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17081689 + 3928324 = 4133^2 + 1982^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010013 - 2⁴ = 21009997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21015013) 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, 10505006 + 10505007.

It is an arithmetic number, because the mean of its divisors is an integer number (10505007).

Almost surely, 2^21010013 is an apocalyptic number.

It is an amenable number.

21010013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010013 is an equidigital number, since it uses as much as digits as its factorization.

21010013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6, while the sum is 8.

The square root of 21010013 is about 4583.6680726248. The cubic root of 21010013 is about 275.9362600481.

Adding to 21010013 its reverse (31001012), we get a palindrome (52011025).

Subtracting 21010013 from its reverse (31001012), we obtain a palindrome (9990999).

The spelling of 21010013 in words is "twenty-one million, ten thousand, thirteen".