21431131237 has 2 divisors, whose sum is σ = 21431131238. Its totient is φ = 21431131236.

The previous prime is 21431131223. The next prime is 21431131259. The reversal of 21431131237 is 73213113412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20369283841 + 1061847396 = 142721^2 + 32586^2 .

It is a cyclic number.

It is not a de Polignac number, because 21431131237 - 2¹⁹ = 21430606949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21431131217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715565618 + 10715565619.

It is an arithmetic number, because the mean of its divisors is an integer number (10715565619).

Almost surely, 2^21431131237 is an apocalyptic number.

It is an amenable number.

21431131237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21431131237 is an equidigital number, since it uses as much as digits as its factorization.

21431131237 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 28.

Adding to 21431131237 its reverse (73213113412), we get a palindrome (94644244649).

The spelling of 21431131237 in words is "twenty-one billion, four hundred thirty-one million, one hundred thirty-one thousand, two hundred thirty-seven".