11661745647961 has 2 divisors, whose sum is σ = 11661745647962. Its totient is φ = 11661745647960.

The previous prime is 11661745647949. The next prime is 11661745647983. The reversal of 11661745647961 is 16974654716611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10624340250000 + 1037405397961 = 3259500^2 + 1018531^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11661745647961 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11661745647893 and 11661745647902.

It is not a weakly prime, because it can be changed into another prime (11661745647901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5830872823980 + 5830872823981.

It is an arithmetic number, because the mean of its divisors is an integer number (5830872823981).

Almost surely, 2^{11661745647961} is an apocalyptic number.

It is an amenable number.

11661745647961 is a deficient number, since it is larger than the sum of its proper divisors (1).

11661745647961 is an equidigital number, since it uses as much as digits as its factorization.

11661745647961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45722880, while the sum is 64.

The spelling of 11661745647961 in words is "eleven trillion, six hundred sixty-one billion, seven hundred forty-five million, six hundred forty-seven thousand, nine hundred sixty-one".