6556116155221 has 2 divisors, whose sum is σ = 6556116155222. Its totient is φ = 6556116155220.

The previous prime is 6556116155119. The next prime is 6556116155257. The reversal of 6556116155221 is 1225516116556.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6550170048900 + 5946106321 = 2559330^2 + 77111^2 .

It is a cyclic number.

It is not a de Polignac number, because 6556116155221 - 2¹¹ = 6556116153173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6556116155021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3278058077610 + 3278058077611.

It is an arithmetic number, because the mean of its divisors is an integer number (3278058077611).

Almost surely, 2^{6556116155221} is an apocalyptic number.

It is an amenable number.

6556116155221 is a deficient number, since it is larger than the sum of its proper divisors (1).

6556116155221 is an equidigital number, since it uses as much as digits as its factorization.

6556116155221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540000, while the sum is 46.

The spelling of 6556116155221 in words is "six trillion, five hundred fifty-six billion, one hundred sixteen million, one hundred fifty-five thousand, two hundred twenty-one".