21131042441 has 2 divisors, whose sum is σ = 21131042442. Its totient is φ = 21131042440.

The previous prime is 21131042437. The next prime is 21131042453. The reversal of 21131042441 is 14424013112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15476604025 + 5654438416 = 124405^2 + 75196^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131042441 - 2² = 21131042437 is a prime.

It is not a weakly prime, because it can be changed into another prime (21131042941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565521220 + 10565521221.

It is an arithmetic number, because the mean of its divisors is an integer number (10565521221).

Almost surely, 2^21131042441 is an apocalyptic number.

It is an amenable number.

21131042441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131042441 is an equidigital number, since it uses as much as digits as its factorization.

21131042441 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 21131042441 its reverse (14424013112), we get a palindrome (35555055553).

The spelling of 21131042441 in words is "twenty-one billion, one hundred thirty-one million, forty-two thousand, four hundred forty-one".