255565391 has 2 divisors, whose sum is σ = 255565392. Its totient is φ = 255565390.

The previous prime is 255565379. The next prime is 255565399. The reversal of 255565391 is 193565552.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-255565391 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (255565399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127782695 + 127782696.

It is an arithmetic number, because the mean of its divisors is an integer number (127782696).

Almost surely, 2^255565391 is an apocalyptic number.

255565391 is a deficient number, since it is larger than the sum of its proper divisors (1).

255565391 is an equidigital number, since it uses as much as digits as its factorization.

255565391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 202500, while the sum is 41.

The square root of 255565391 is about 15986.4126995396. The cubic root of 255565391 is about 634.6008949726.

The spelling of 255565391 in words is "two hundred fifty-five million, five hundred sixty-five thousand, three hundred ninety-one".