1378756742666 has 16 divisors (see below), whose sum is σ = 2163488891400. Its totient is φ = 658127973888.

The previous prime is 1378756742663. The next prime is 1378756742687. The reversal of 1378756742666 is 6662476578731.

It can be written as a sum of positive squares in 4 ways, for example, as 975304380625 + 403452362041 = 987575^2 + 635179^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1378756742596 and 1378756742605.

It is not an unprimeable number, because it can be changed into a prime (1378756742663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133543535 + ... + 133553858.

Almost surely, 2^{1378756742666} is an apocalyptic number.

1378756742666 is a deficient number, since it is larger than the sum of its proper divisors (784732148734).

1378756742666 is a wasteful number, since it uses less digits than its factorization.

1378756742666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267097513.

The product of its digits is 426746880, while the sum is 68.

The spelling of 1378756742666 in words is "one trillion, three hundred seventy-eight billion, seven hundred fifty-six million, seven hundred forty-two thousand, six hundred sixty-six".