1278721387834 has 24 divisors (see below), whose sum is σ = 2108550931200. Its totient is φ = 581169221160.

The previous prime is 1278721387819. The next prime is 1278721387877. The reversal of 1278721387834 is 4387831278721.

It is a happy number.

It is a super-2 number, since 2×1278721387834² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1801447 + ... + 2408869.

It is an arithmetic number, because the mean of its divisors is an integer number (87856288800).

Almost surely, 2^{1278721387834} is an apocalyptic number.

1278721387834 is a deficient number, since it is larger than the sum of its proper divisors (829829543366).

1278721387834 is a wasteful number, since it uses less digits than its factorization.

1278721387834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616146 (or 616135 counting only the distinct ones).

The product of its digits is 25288704, while the sum is 61.

The spelling of 1278721387834 in words is "one trillion, two hundred seventy-eight billion, seven hundred twenty-one million, three hundred eighty-seven thousand, eight hundred thirty-four".