21016013 has 2 divisors, whose sum is σ = 21016014. Its totient is φ = 21016012.

The previous prime is 21016007. The next prime is 21016027. The reversal of 21016013 is 31061012.

It is an a-pointer prime, because the next prime (21016027) can be obtained adding 21016013 to its sum of digits (14).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20912329 + 103684 = 4573^2 + 322^2 .

It is a cyclic number.

It is not a de Polignac number, because 21016013 - 2¹⁰ = 21014989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21016613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10508006 + 10508007.

It is an arithmetic number, because the mean of its divisors is an integer number (10508007).

Almost surely, 2^21016013 is an apocalyptic number.

It is an amenable number.

21016013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21016013 is an equidigital number, since it uses as much as digits as its factorization.

21016013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 21016013 is about 4584.3225235579. The cubic root of 21016013 is about 275.9625246675.

Adding to 21016013 its reverse (31061012), we get a palindrome (52077025).

The spelling of 21016013 in words is "twenty-one million, sixteen thousand, thirteen".