255721187 has 2 divisors, whose sum is σ = 255721188. Its totient is φ = 255721186.

The previous prime is 255721177. The next prime is 255721189. The reversal of 255721187 is 781127552.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 255721187 - 2⁸ = 255720931 is a prime.

Together with 255721189, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 255721187.

It is not a weakly prime, because it can be changed into another prime (255721189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127860593 + 127860594.

It is an arithmetic number, because the mean of its divisors is an integer number (127860594).

Almost surely, 2^255721187 is an apocalyptic number.

255721187 is a deficient number, since it is larger than the sum of its proper divisors (1).

255721187 is an equidigital number, since it uses as much as digits as its factorization.

255721187 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39200, while the sum is 38.

The square root of 255721187 is about 15991.2847201218. The cubic root of 255721187 is about 634.7298224420.

The spelling of 255721187 in words is "two hundred fifty-five million, seven hundred twenty-one thousand, one hundred eighty-seven".