1281289320840 has 64 divisors (see below), whose sum is σ = 3867450033600. Its totient is φ = 339580968192.

The previous prime is 1281289320823. The next prime is 1281289320841. The reversal of 1281289320840 is 480239821821.

It is a self number, because there is not a number n which added to its sum of digits gives 1281289320840.

It is not an unprimeable number, because it can be changed into a prime (1281289320841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32733235 + ... + 32772354.

It is an arithmetic number, because the mean of its divisors is an integer number (60428906775).

Almost surely, 2^{1281289320840} is an apocalyptic number.

1281289320840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1281289320840 is an abundant number, since it is smaller than the sum of its proper divisors (2586160712760).

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

1281289320840 is a wasteful number, since it uses less digits than its factorization.

1281289320840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65505766 (or 65505762 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 48.

The spelling of 1281289320840 in words is "one trillion, two hundred eighty-one billion, two hundred eighty-nine million, three hundred twenty thousand, eight hundred forty".