21036013 has 2 divisors, whose sum is σ = 21036014. Its totient is φ = 21036012.

The previous prime is 21035981. The next prime is 21036023. The reversal of 21036013 is 31063012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19245769 + 1790244 = 4387^2 + 1338^2 .

It is a cyclic number.

It is not a de Polignac number, because 21036013 - 2⁵ = 21035981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21036023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10518006 + 10518007.

It is an arithmetic number, because the mean of its divisors is an integer number (10518007).

Almost surely, 2^21036013 is an apocalyptic number.

It is an amenable number.

21036013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21036013 is an equidigital number, since it uses as much as digits as its factorization.

21036013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 16.

The square root of 21036013 is about 4586.5033522281. The cubic root of 21036013 is about 276.0500373118.

Adding to 21036013 its reverse (31063012), we get a palindrome (52099025).

The spelling of 21036013 in words is "twenty-one million, thirty-six thousand, thirteen".