255571721 has 2 divisors, whose sum is σ = 255571722. Its totient is φ = 255571720.

The previous prime is 255571711. The next prime is 255571753. The reversal of 255571721 is 127175552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 220938496 + 34633225 = 14864^2 + 5885^2 .

It is a cyclic number.

It is not a de Polignac number, because 255571721 - 2¹⁰ = 255570697 is a prime.

It is not a weakly prime, because it can be changed into another prime (255571711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127785860 + 127785861.

It is an arithmetic number, because the mean of its divisors is an integer number (127785861).

Almost surely, 2^255571721 is an apocalyptic number.

It is an amenable number.

255571721 is a deficient number, since it is larger than the sum of its proper divisors (1).

255571721 is an equidigital number, since it uses as much as digits as its factorization.

255571721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24500, while the sum is 35.

The square root of 255571721 is about 15986.6106789400. The cubic root of 255571721 is about 634.6061343238.

The spelling of 255571721 in words is "two hundred fifty-five million, five hundred seventy-one thousand, seven hundred twenty-one".