21131121284737 has 2 divisors, whose sum is σ = 21131121284738. Its totient is φ = 21131121284736.

The previous prime is 21131121284699. The next prime is 21131121284803. The reversal of 21131121284737 is 73748212113112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20272902471936 + 858218812801 = 4502544^2 + 926401^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131121284737 - 2³⁹ = 20581365470849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21131121284693 and 21131121284702.

It is not a weakly prime, because it can be changed into another prime (21131121284437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565560642368 + 10565560642369.

It is an arithmetic number, because the mean of its divisors is an integer number (10565560642369).

Almost surely, 2^{21131121284737} is an apocalyptic number.

It is an amenable number.

21131121284737 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131121284737 is an equidigital number, since it uses as much as digits as its factorization.

21131121284737 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 112896, while the sum is 43.

Adding to 21131121284737 its reverse (73748212113112), we get a palindrome (94879333397849).

The spelling of 21131121284737 in words is "twenty-one trillion, one hundred thirty-one billion, one hundred twenty-one million, two hundred eighty-four thousand, seven hundred thirty-seven".