1311981278 has 8 divisors (see below), whose sum is σ = 1968390072. Its totient is φ = 655851256.

The previous prime is 1311981271. The next prime is 1311981313. The reversal of 1311981278 is 8721891131.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311981271) 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 3 ways as a sum of consecutive naturals, for example, 57500 + ... + 77007.

It is an arithmetic number, because the mean of its divisors is an integer number (246048759).

Almost surely, 2^1311981278 is an apocalyptic number.

1311981278 is a deficient number, since it is larger than the sum of its proper divisors (656408794).

1311981278 is a wasteful number, since it uses less digits than its factorization.

1311981278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139386.

The product of its digits is 24192, while the sum is 41.

The square root of 1311981278 is about 36221.2821142488. The cubic root of 1311981278 is about 1094.7355276849.

The spelling of 1311981278 in words is "one billion, three hundred eleven million, nine hundred eighty-one thousand, two hundred seventy-eight".