1278395827477 has 2 divisors, whose sum is σ = 1278395827478. Its totient is φ = 1278395827476.

The previous prime is 1278395827459. The next prime is 1278395827549. The reversal of 1278395827477 is 7747285938721.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1216606794001 + 61789033476 = 1102999^2 + 248574^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1278395827477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1278395827427) by changing a digit.

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 as a sum of consecutive naturals, namely, 639197913738 + 639197913739.

It is an arithmetic number, because the mean of its divisors is an integer number (639197913739).

Almost surely, 2^{1278395827477} is an apocalyptic number.

It is an amenable number.

1278395827477 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278395827477 is an equidigital number, since it uses as much as digits as its factorization.

1278395827477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 331914240, while the sum is 70.

The spelling of 1278395827477 in words is "one trillion, two hundred seventy-eight billion, three hundred ninety-five million, eight hundred twenty-seven thousand, four hundred seventy-seven".