21044237 has 2 divisors, whose sum is σ = 21044238. Its totient is φ = 21044236.

The previous prime is 21044213. The next prime is 21044251. The reversal of 21044237 is 73244012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14638276 + 6405961 = 3826^2 + 2531^2 .

It is a cyclic number.

It is not a de Polignac number, because 21044237 - 2¹⁶ = 20978701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21043237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522118 + 10522119.

It is an arithmetic number, because the mean of its divisors is an integer number (10522119).

Almost surely, 2^21044237 is an apocalyptic number.

It is an amenable number.

21044237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21044237 is an equidigital number, since it uses as much as digits as its factorization.

21044237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 21044237 is about 4587.3998081702. The cubic root of 21044237 is about 276.0860064174.

Adding to 21044237 its reverse (73244012), we get a palindrome (94288249).

The spelling of 21044237 in words is "twenty-one million, forty-four thousand, two hundred thirty-seven".