19545909661 has 2 divisors, whose sum is σ = 19545909662. Its totient is φ = 19545909660.

The previous prime is 19545909641. The next prime is 19545909667. The reversal of 19545909661 is 16690954591.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10496002500 + 9049907161 = 102450^2 + 95131^2 .

It is a cyclic number.

It is not a de Polignac number, because 19545909661 - 2⁵ = 19545909629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19545909667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9772954830 + 9772954831.

It is an arithmetic number, because the mean of its divisors is an integer number (9772954831).

Almost surely, 2^19545909661 is an apocalyptic number.

It is an amenable number.

19545909661 is a deficient number, since it is larger than the sum of its proper divisors (1).

19545909661 is an equidigital number, since it uses as much as digits as its factorization.

19545909661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2624400, while the sum is 55.

The spelling of 19545909661 in words is "nineteen billion, five hundred forty-five million, nine hundred nine thousand, six hundred sixty-one".