21204131237 has 2 divisors, whose sum is σ = 21204131238. Its totient is φ = 21204131236.

The previous prime is 21204131219. The next prime is 21204131269. The reversal of 21204131237 is 73213140212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15237186721 + 5966944516 = 123439^2 + 77246^2 .

It is a cyclic number.

It is not a de Polignac number, because 21204131237 - 2¹² = 21204127141 is a prime.

It is a super-3 number, since 3×21204131237³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21204136237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602065618 + 10602065619.

It is an arithmetic number, because the mean of its divisors is an integer number (10602065619).

Almost surely, 2^21204131237 is an apocalyptic number.

It is an amenable number.

21204131237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204131237 is an equidigital number, since it uses as much as digits as its factorization.

21204131237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 26.

Adding to 21204131237 its reverse (73213140212), we get a palindrome (94417271449).

The spelling of 21204131237 in words is "twenty-one billion, two hundred four million, one hundred thirty-one thousand, two hundred thirty-seven".