15551436853681 has 2 divisors, whose sum is σ = 15551436853682. Its totient is φ = 15551436853680.

The previous prime is 15551436853627. The next prime is 15551436853717. The reversal of 15551436853681 is 18635863415551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9474028596081 + 6077408257600 = 3077991^2 + 2465240^2 .

It is a cyclic number.

It is not a de Polignac number, because 15551436853681 - 2⁷ = 15551436853553 is a prime.

It is a super-2 number, since 2×15551436853681² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (15551436853081) 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, 7775718426840 + 7775718426841.

It is an arithmetic number, because the mean of its divisors is an integer number (7775718426841).

Almost surely, 2^{15551436853681} is an apocalyptic number.

It is an amenable number.

15551436853681 is a deficient number, since it is larger than the sum of its proper divisors (1).

15551436853681 is an equidigital number, since it uses as much as digits as its factorization.

15551436853681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840000, while the sum is 61.

The spelling of 15551436853681 in words is "fifteen trillion, five hundred fifty-one billion, four hundred thirty-six million, eight hundred fifty-three thousand, six hundred eighty-one".