1289821312 has 64 divisors (see below), whose sum is σ = 2775560760. Its totient is φ = 593510400.

The previous prime is 1289821283. The next prime is 1289821321. The reversal of 1289821312 is 2131289821.

It can be written as a sum of positive squares in 4 ways, for example, as 1259966016 + 29855296 = 35496^2 + 5464^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 666298 + ... + 668230.

Almost surely, 2^1289821312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1289821312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1387780380).

1289821312 is an abundant number, since it is smaller than the sum of its proper divisors (1485739448).

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

1289821312 is a wasteful number, since it uses less digits than its factorization.

1289821312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2361 (or 2349 counting only the distinct ones).

The product of its digits is 13824, while the sum is 37.

The square root of 1289821312 is about 35914.0823633293. The cubic root of 1289821312 is about 1088.5369682184.

It can be divided in two parts, 128 and 9821312, that multiplied together give a square (1257127936 = 35456²).

The spelling of 1289821312 in words is "one billion, two hundred eighty-nine million, eight hundred twenty-one thousand, three hundred twelve".