15543667121 has 2 divisors, whose sum is σ = 15543667122. Its totient is φ = 15543667120.

The previous prime is 15543667049. The next prime is 15543667169. The reversal of 15543667121 is 12176634551.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13378160896 + 2165506225 = 115664^2 + 46535^2 .

It is a cyclic number.

It is not a de Polignac number, because 15543667121 - 2¹⁰ = 15543666097 is a prime.

It is not a weakly prime, because it can be changed into another prime (15543667621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7771833560 + 7771833561.

It is an arithmetic number, because the mean of its divisors is an integer number (7771833561).

Almost surely, 2^15543667121 is an apocalyptic number.

It is an amenable number.

15543667121 is a deficient number, since it is larger than the sum of its proper divisors (1).

15543667121 is an equidigital number, since it uses as much as digits as its factorization.

15543667121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 151200, while the sum is 41.

The spelling of 15543667121 in words is "fifteen billion, five hundred forty-three million, six hundred sixty-seven thousand, one hundred twenty-one".