21037837 has 2 divisors, whose sum is σ = 21037838. Its totient is φ = 21037836.

The previous prime is 21037829. The next prime is 21037859. The reversal of 21037837 is 73873012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10982596 + 10055241 = 3314^2 + 3171^2 .

It is a cyclic number.

It is not a de Polignac number, because 21037837 - 2³ = 21037829 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21037799 and 21037808.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21037817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10518918 + 10518919.

It is an arithmetic number, because the mean of its divisors is an integer number (10518919).

Almost surely, 2^21037837 is an apocalyptic number.

It is an amenable number.

21037837 is a deficient number, since it is larger than the sum of its proper divisors (1).

21037837 is an equidigital number, since it uses as much as digits as its factorization.

21037837 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 21037837 is about 4586.7021922074. The cubic root of 21037837 is about 276.0580157044.

The spelling of 21037837 in words is "twenty-one million, thirty-seven thousand, eight hundred thirty-seven".