21031402237 has 2 divisors, whose sum is σ = 21031402238. Its totient is φ = 21031402236.

The previous prime is 21031402229. The next prime is 21031402241. The reversal of 21031402237 is 73220413012.

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., 16469615556 + 4561786681 = 128334^2 + 67541^2 .

It is a cyclic number.

It is not a de Polignac number, because 21031402237 - 2³ = 21031402229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21031402037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515701118 + 10515701119.

It is an arithmetic number, because the mean of its divisors is an integer number (10515701119).

Almost surely, 2^21031402237 is an apocalyptic number.

It is an amenable number.

21031402237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031402237 is an equidigital number, since it uses as much as digits as its factorization.

21031402237 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 25.

Adding to 21031402237 its reverse (73220413012), we get a palindrome (94251815249).

The spelling of 21031402237 in words is "twenty-one billion, thirty-one million, four hundred two thousand, two hundred thirty-seven".