255721549 has 2 divisors, whose sum is σ = 255721550. Its totient is φ = 255721548.

The previous prime is 255721493. The next prime is 255721553. The reversal of 255721549 is 945127552.

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., 165945924 + 89775625 = 12882^2 + 9475^2 .

It is a cyclic number.

It is not a de Polignac number, because 255721549 - 2⁷ = 255721421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (255721579) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127860774 + 127860775.

It is an arithmetic number, because the mean of its divisors is an integer number (127860775).

Almost surely, 2^255721549 is an apocalyptic number.

It is an amenable number.

255721549 is a deficient number, since it is larger than the sum of its proper divisors (1).

255721549 is an equidigital number, since it uses as much as digits as its factorization.

255721549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 126000, while the sum is 40.

The square root of 255721549 is about 15991.2960387831. The cubic root of 255721549 is about 634.7301219506.

The spelling of 255721549 in words is "two hundred fifty-five million, seven hundred twenty-one thousand, five hundred forty-nine".