2556216181 has 2 divisors, whose sum is σ = 2556216182. Its totient is φ = 2556216180.

The previous prime is 2556216097. The next prime is 2556216191. The reversal of 2556216181 is 1816126552.

2556216181 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1655676100 + 900540081 = 40690^2 + 30009^2 .

It is a cyclic number.

It is not a de Polignac number, because 2556216181 - 2¹⁷ = 2556085109 is a prime.

It is a super-2 number, since 2×2556216181² = 13068482328012449522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2556216181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2556216191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1278108090 + 1278108091.

It is an arithmetic number, because the mean of its divisors is an integer number (1278108091).

Almost surely, 2^2556216181 is an apocalyptic number.

It is an amenable number.

2556216181 is a deficient number, since it is larger than the sum of its proper divisors (1).

2556216181 is an equidigital number, since it uses as much as digits as its factorization.

2556216181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 37.

The square root of 2556216181 is about 50559.0365909003. The cubic root of 2556216181 is about 1367.3064417283.

The spelling of 2556216181 in words is "two billion, five hundred fifty-six million, two hundred sixteen thousand, one hundred eighty-one".