268781 has 2 divisors, whose sum is σ = 268782. Its totient is φ = 268780.

The previous prime is 268777. The next prime is 268783. The reversal of 268781 is 187862.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198025 + 70756 = 445^2 + 266^2 .

It is a cyclic number.

It is not a de Polignac number, because 268781 - 2² = 268777 is a prime.

It is a super-2 number, since 2×268781² = 144486451922, which contains 22 as substring.

Together with 268783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (268783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 134390 + 134391.

It is an arithmetic number, because the mean of its divisors is an integer number (134391).

2²⁶⁸⁷⁸¹ is an apocalyptic number.

It is an amenable number.

268781 is a deficient number, since it is larger than the sum of its proper divisors (1).

268781 is an equidigital number, since it uses as much as digits as its factorization.

268781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 32.

The square root of 268781 is about 518.4409320260. The cubic root of 268781 is about 64.5356252127.

The spelling of 268781 in words is "two hundred sixty-eight thousand, seven hundred eighty-one".