1291780177768 has 8 divisors (see below), whose sum is σ = 2422087833330. Its totient is φ = 645890088880.

The previous prime is 1291780177763. The next prime is 1291780177813. The reversal of 1291780177768 is 8677710871921.

It can be written as a sum of positive squares in only one way, i.e., 1286550284644 + 5229893124 = 1134262^2 + 72318^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (1291780177763) 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 as a sum of consecutive naturals, namely, 80736261103 + ... + 80736261118.

Almost surely, 2^{1291780177768} is an apocalyptic number.

It is an amenable number.

1291780177768 is a deficient number, since it is larger than the sum of its proper divisors (1130307655562).

1291780177768 is a wasteful number, since it uses less digits than its factorization.

1291780177768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161472522227 (or 161472522223 counting only the distinct ones).

The product of its (nonzero) digits is 16595712, while the sum is 64.

The spelling of 1291780177768 in words is "one trillion, two hundred ninety-one billion, seven hundred eighty million, one hundred seventy-seven thousand, seven hundred sixty-eight".