1280390660 has 12 divisors (see below), whose sum is σ = 2688820428. Its totient is φ = 512156256.

The previous prime is 1280390659. The next prime is 1280390663. The reversal of 1280390660 is 660930821.

It can be written as a sum of positive squares in 2 ways, for example, as 994645444 + 285745216 = 31538^2 + 16904^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1280390660.

It is not an unprimeable number, because it can be changed into a prime (1280390663) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 32009747 + ... + 32009786.

It is an arithmetic number, because the mean of its divisors is an integer number (224068369).

Almost surely, 2^1280390660 is an apocalyptic number.

1280390660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1280390660 is an abundant number, since it is smaller than the sum of its proper divisors (1408429768).

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

1280390660 is a wasteful number, since it uses less digits than its factorization.

1280390660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64019542 (or 64019540 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 1280390660 is about 35782.5468629610. The cubic root of 1280390660 is about 1085.8774952342.

The spelling of 1280390660 in words is "one billion, two hundred eighty million, three hundred ninety thousand, six hundred sixty".