257720563 has 2 divisors, whose sum is σ = 257720564.
Its totient is φ = 257720562.
The previous prime is 257720549. The next prime is 257720621. The reversal of 257720563 is 365027752.
It is a weak prime.
It is a cyclic number.
It is not a de Polignac number, because 257720563 - 25 = 257720531 is a prime.
It is equal to p14078278 and since 257720563 and 14078278 have the same sum of digits, it is a Honaker prime.
It is not a weakly prime, because it can be changed into another prime (257720513) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128860281 + 128860282.
It is an arithmetic number, because the mean of its divisors is an integer number (128860282).
Almost surely, 2257720563 is an apocalyptic number.
257720563 is a deficient number, since it is larger than the sum of its proper divisors (1).
257720563 is an equidigital number, since it uses as much as digits as its factorization.
257720563 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 88200, while the sum is 37.
The square root of 257720563 is about 16053.6775537570.
The cubic root of 257720563 is about 636.3797580041.
The spelling of 257720563 in words is "two hundred fifty-seven million, seven hundred twenty thousand, five hundred sixty-three".