1289990720 has 28 divisors (see below), whose sum is σ = 3071791164. Its totient is φ = 515996160.

The previous prime is 1289990707. The next prime is 1289990761. The reversal of 1289990720 is 270999821.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 865301056 + 424689664 = 29416^2 + 20608^2 .

It is a super-2 number, since 2×1289990720² = 3328152115372236800, which contains 22 as substring.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 2015291 + ... + 2015930.

Almost surely, 2^1289990720 is an apocalyptic number.

1289990720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1289990720 is an abundant number, since it is smaller than the sum of its proper divisors (1781800444).

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

1289990720 is an equidigital number, since it uses as much as digits as its factorization.

1289990720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4031238 (or 4031228 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 1289990720 is about 35916.4408036208. The cubic root of 1289990720 is about 1088.5846230876.

The spelling of 1289990720 in words is "one billion, two hundred eighty-nine million, nine hundred ninety thousand, seven hundred twenty".