268128691 has 2 divisors, whose sum is σ = 268128692. Its totient is φ = 268128690.

The previous prime is 268128689. The next prime is 268128713. The reversal of 268128691 is 196821862.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 268128691 - 2¹ = 268128689 is a prime.

Together with 268128689, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (268128631) 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, 134064345 + 134064346.

It is an arithmetic number, because the mean of its divisors is an integer number (134064346).

Almost surely, 2^268128691 is an apocalyptic number.

268128691 is a deficient number, since it is larger than the sum of its proper divisors (1).

268128691 is an equidigital number, since it uses as much as digits as its factorization.

268128691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 43.

The square root of 268128691 is about 16374.6355989988. The cubic root of 268128691 is about 644.8337540016.

The spelling of 268128691 in words is "two hundred sixty-eight million, one hundred twenty-eight thousand, six hundred ninety-one".