21115514135461 has 2 divisors, whose sum is σ = 21115514135462. Its totient is φ = 21115514135460.

The previous prime is 21115514135323. The next prime is 21115514135467. The reversal of 21115514135461 is 16453141551112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13244577276100 + 7870936859361 = 3639310^2 + 2805519^2 .

It is a cyclic number.

It is not a de Polignac number, because 21115514135461 - 2¹⁹ = 21115513611173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115514135467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557757067730 + 10557757067731.

It is an arithmetic number, because the mean of its divisors is an integer number (10557757067731).

Almost surely, 2^{21115514135461} is an apocalyptic number.

It is an amenable number.

21115514135461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115514135461 is an equidigital number, since it uses as much as digits as its factorization.

21115514135461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72000, while the sum is 40.

Adding to 21115514135461 its reverse (16453141551112), we get a palindrome (37568655686573).

The spelling of 21115514135461 in words is "twenty-one trillion, one hundred fifteen billion, five hundred fourteen million, one hundred thirty-five thousand, four hundred sixty-one".