2121311431517 has 2 divisors, whose sum is σ = 2121311431518. Its totient is φ = 2121311431516.

The previous prime is 2121311431433. The next prime is 2121311431559. The reversal of 2121311431517 is 7151341131212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1902824366041 + 218487065476 = 1379429^2 + 467426^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121311431517 - 2²⁴ = 2121294654301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121311431567) 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, 1060655715758 + 1060655715759.

It is an arithmetic number, because the mean of its divisors is an integer number (1060655715759).

Almost surely, 2^{2121311431517} is an apocalyptic number.

It is an amenable number.

2121311431517 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121311431517 is an equidigital number, since it uses as much as digits as its factorization.

2121311431517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5040, while the sum is 32.

Adding to 2121311431517 its reverse (7151341131212), we get a palindrome (9272652562729).

The spelling of 2121311431517 in words is "two trillion, one hundred twenty-one billion, three hundred eleven million, four hundred thirty-one thousand, five hundred seventeen".