1277876387861 has 2 divisors, whose sum is σ = 1277876387862. Its totient is φ = 1277876387860.

The previous prime is 1277876387839. The next prime is 1277876387881. The reversal of 1277876387861 is 1687836787721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1034512752100 + 243363635761 = 1017110^2 + 493319^2 .

It is a cyclic number.

It is not a de Polignac number, because 1277876387861 - 2¹⁰ = 1277876386837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1277876387881) 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, 638938193930 + 638938193931.

It is an arithmetic number, because the mean of its divisors is an integer number (638938193931).

Almost surely, 2^{1277876387861} is an apocalyptic number.

It is an amenable number.

1277876387861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1277876387861 is an equidigital number, since it uses as much as digits as its factorization.

1277876387861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 265531392, while the sum is 71.

The spelling of 1277876387861 in words is "one trillion, two hundred seventy-seven billion, eight hundred seventy-six million, three hundred eighty-seven thousand, eight hundred sixty-one".