1281378386838 has 16 divisors (see below), whose sum is σ = 2795734662336. Its totient is φ = 388296480840.

The previous prime is 1281378386669. The next prime is 1281378386857. The reversal of 1281378386838 is 8386838731821.

It is a Harshad number since it is a multiple of its sum of digits (66), and also a Moran number because the ratio is a prime number: 19414824043 = 1281378386838 / (1 + 2 + 8 + 1 + 3 + 7 + 8 + 3 + 8 + 6 + 8 + 3 + 8).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9707411956 + ... + 9707412087.

It is an arithmetic number, because the mean of its divisors is an integer number (174733416396).

Almost surely, 2^{1281378386838} is an apocalyptic number.

1281378386838 is an abundant number, since it is smaller than the sum of its proper divisors (1514356275498).

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

1281378386838 is a wasteful number, since it uses less digits than its factorization.

1281378386838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19414824059.

The product of its digits is 74317824, while the sum is 66.

The spelling of 1281378386838 in words is "one trillion, two hundred eighty-one billion, three hundred seventy-eight million, three hundred eighty-six thousand, eight hundred thirty-eight".