1289387280 has 80 divisors (see below), whose sum is σ = 4004457984. Its totient is φ = 343203840.

The previous prime is 1289387279. The next prime is 1289387369. The reversal of 1289387280 is 827839821.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 133825 + ... + 143135.

Almost surely, 2^1289387280 is an apocalyptic number.

1289387280 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1289387280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2002228992).

1289387280 is an abundant number, since it is smaller than the sum of its proper divisors (2715070704).

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

1289387280 is a wasteful number, since it uses less digits than its factorization.

1289387280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9904 (or 9898 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 48.

The square root of 1289387280 is about 35908.0392112964. The cubic root of 1289387280 is about 1088.4148549515.

The spelling of 1289387280 in words is "one billion, two hundred eighty-nine million, three hundred eighty-seven thousand, two hundred eighty".