21210313237 has 2 divisors, whose sum is σ = 21210313238. Its totient is φ = 21210313236.

The previous prime is 21210313199. The next prime is 21210313261. The reversal of 21210313237 is 73231301212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15322973796 + 5887339441 = 123786^2 + 76729^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210313237 - 2¹⁹ = 21209788949 is a prime.

It is a super-2 number, since 2×21210313237² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210313337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605156618 + 10605156619.

It is an arithmetic number, because the mean of its divisors is an integer number (10605156619).

Almost surely, 2^21210313237 is an apocalyptic number.

It is an amenable number.

21210313237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210313237 is an equidigital number, since it uses as much as digits as its factorization.

21210313237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 25.

Adding to 21210313237 its reverse (73231301212), we get a palindrome (94441614449).

The spelling of 21210313237 in words is "twenty-one billion, two hundred ten million, three hundred thirteen thousand, two hundred thirty-seven".