255866381 has 2 divisors, whose sum is σ = 255866382. Its totient is φ = 255866380.

The previous prime is 255866323. The next prime is 255866389. The reversal of 255866381 is 183668552.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 253892356 + 1974025 = 15934^2 + 1405^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-255866381 is a prime.

It is a super-2 number, since 2×255866381² = 130935209852074322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (255866389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127933190 + 127933191.

It is an arithmetic number, because the mean of its divisors is an integer number (127933191).

Almost surely, 2^255866381 is an apocalyptic number.

It is an amenable number.

255866381 is a deficient number, since it is larger than the sum of its proper divisors (1).

255866381 is an equidigital number, since it uses as much as digits as its factorization.

255866381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 345600, while the sum is 44.

The square root of 255866381 is about 15995.8238612458. The cubic root of 255866381 is about 634.8499291962.

The spelling of 255866381 in words is "two hundred fifty-five million, eight hundred sixty-six thousand, three hundred eighty-one".