1228391 has 2 divisors, whose sum is σ = 1228392. Its totient is φ = 1228390.

The previous prime is 1228373. The next prime is 1228393. The reversal of 1228391 is 1938221.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1228391 - 2⁶ = 1228327 is a prime.

Together with 1228393, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1228391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1228393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 614195 + 614196.

It is an arithmetic number, because the mean of its divisors is an integer number (614196).

2^1228391 is an apocalyptic number.

1228391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1228391 is an equidigital number, since it uses as much as digits as its factorization.

1228391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 26.

The square root of 1228391 is about 1108.3280200374. The cubic root of 1228391 is about 107.0973870974.

The spelling of 1228391 in words is "one million, two hundred twenty-eight thousand, three hundred ninety-one".