1289856 has 32 divisors (see below), whose sum is σ = 3427200. Its totient is φ = 429824.

The previous prime is 1289851. The next prime is 1289867. The reversal of 1289856 is 6589821.

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (1289851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1296 + ... + 2063.

It is an arithmetic number, because the mean of its divisors is an integer number (107100).

2^1289856 is an apocalyptic number.

1289856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1289856 is an abundant number, since it is smaller than the sum of its proper divisors (2137344).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1289856 is an equidigital number, since it uses as much as digits as its factorization.

1289856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3376 (or 3364 counting only the distinct ones).

The product of its digits is 34560, while the sum is 39.

The square root of 1289856 is about 1135.7182749256. The cubic root of 1289856 is about 108.8546726374.

It can be divided in two parts, 1289 and 856, that added together give a triangular number (2145 = T₆₅).

The spelling of 1289856 in words is "one million, two hundred eighty-nine thousand, eight hundred fifty-six".