1285811 has 2 divisors, whose sum is σ = 1285812. Its totient is φ = 1285810.

The previous prime is 1285799. The next prime is 1285813. The reversal of 1285811 is 1185821.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1285811 - 2⁶ = 1285747 is a prime.

Together with 1285813, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1285813) 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, 642905 + 642906.

It is an arithmetic number, because the mean of its divisors is an integer number (642906).

2^1285811 is an apocalyptic number.

1285811 is a deficient number, since it is larger than the sum of its proper divisors (1).

1285811 is an equidigital number, since it uses as much as digits as its factorization.

1285811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 640, while the sum is 26.

The square root of 1285811 is about 1133.9360652171. The cubic root of 1285811 is about 108.7407637375.

The spelling of 1285811 in words is "one million, two hundred eighty-five thousand, eight hundred eleven".