21037013 has 2 divisors, whose sum is σ = 21037014. Its totient is φ = 21037012.

The previous prime is 21036991. The next prime is 21037021. The reversal of 21037013 is 31073012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21003889 + 33124 = 4583^2 + 182^2 .

It is a cyclic number.

It is not a de Polignac number, because 21037013 - 2¹⁸ = 20774869 is a prime.

It is a zygodrome in base 4.

It is a junction number, because it is equal to n+sod(n) for n = 21036982 and 21037000.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21037813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10518506 + 10518507.

It is an arithmetic number, because the mean of its divisors is an integer number (10518507).

Almost surely, 2^21037013 is an apocalyptic number.

It is an amenable number.

21037013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21037013 is an equidigital number, since it uses as much as digits as its factorization.

21037013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 126, while the sum is 17.

The square root of 21037013 is about 4586.6123664421. The cubic root of 21037013 is about 276.0544114877.

The spelling of 21037013 in words is "twenty-one million, thirty-seven thousand, thirteen".