19847209766261 has 2 divisors, whose sum is σ = 19847209766262. Its totient is φ = 19847209766260.

The previous prime is 19847209766207. The next prime is 19847209766291. The reversal of 19847209766261 is 16266790274891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10073520602161 + 9773689164100 = 3173881^2 + 3126290^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19847209766261 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19847209766191 and 19847209766200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19847209766291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9923604883130 + 9923604883131.

It is an arithmetic number, because the mean of its divisors is an integer number (9923604883131).

Almost surely, 2^{19847209766261} is an apocalyptic number.

It is an amenable number.

19847209766261 is a deficient number, since it is larger than the sum of its proper divisors (1).

19847209766261 is an equidigital number, since it uses as much as digits as its factorization.

19847209766261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 109734912, while the sum is 68.

The spelling of 19847209766261 in words is "nineteen trillion, eight hundred forty-seven billion, two hundred nine million, seven hundred sixty-six thousand, two hundred sixty-one".