19160721436861 has 2 divisors, whose sum is σ = 19160721436862. Its totient is φ = 19160721436860.

The previous prime is 19160721436841. The next prime is 19160721436889. The reversal of 19160721436861 is 16863412706191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16599969381636 + 2560752055225 = 4074306^2 + 1600235^2 .

It is a cyclic number.

It is not a de Polignac number, because 19160721436861 - 2¹⁹ = 19160720912573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19160721436841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9580360718430 + 9580360718431.

It is an arithmetic number, because the mean of its divisors is an integer number (9580360718431).

Almost surely, 2^{19160721436861} is an apocalyptic number.

It is an amenable number.

19160721436861 is a deficient number, since it is larger than the sum of its proper divisors (1).

19160721436861 is an equidigital number, since it uses as much as digits as its factorization.

19160721436861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2612736, while the sum is 55.

The spelling of 19160721436861 in words is "nineteen trillion, one hundred sixty billion, seven hundred twenty-one million, four hundred thirty-six thousand, eight hundred sixty-one".