1261503774673 has 2 divisors, whose sum is σ = 1261503774674. Its totient is φ = 1261503774672.

The previous prime is 1261503774667. The next prime is 1261503774737. The reversal of 1261503774673 is 3764773051621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 771626966929 + 489876807744 = 878423^2 + 699912^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1261503774673 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1261503774673.

It is not a weakly prime, because it can be changed into another prime (1261503774653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630751887336 + 630751887337.

It is an arithmetic number, because the mean of its divisors is an integer number (630751887337).

Almost surely, 2^{1261503774673} is an apocalyptic number.

It is an amenable number.

1261503774673 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261503774673 is an equidigital number, since it uses as much as digits as its factorization.

1261503774673 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4445280, while the sum is 52.

The spelling of 1261503774673 in words is "one trillion, two hundred sixty-one billion, five hundred three million, seven hundred seventy-four thousand, six hundred seventy-three".