19361698721 has 2 divisors, whose sum is σ = 19361698722. Its totient is φ = 19361698720.

The previous prime is 19361698669. The next prime is 19361698777. The reversal of 19361698721 is 12789616391.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18430777600 + 930921121 = 135760^2 + 30511^2 .

It is a cyclic number.

It is not a de Polignac number, because 19361698721 - 2¹⁰ = 19361697697 is a prime.

It is not a weakly prime, because it can be changed into another prime (19361698621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9680849360 + 9680849361.

It is an arithmetic number, because the mean of its divisors is an integer number (9680849361).

Almost surely, 2^19361698721 is an apocalyptic number.

It is an amenable number.

19361698721 is a deficient number, since it is larger than the sum of its proper divisors (1).

19361698721 is an equidigital number, since it uses as much as digits as its factorization.

19361698721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 53.

The spelling of 19361698721 in words is "nineteen billion, three hundred sixty-one million, six hundred ninety-eight thousand, seven hundred twenty-one".