19204693561 has 3 divisors (see below), whose sum is σ = 19204832143. Its totient is φ = 19204554980.

The previous prime is 19204693531. The next prime is 19204693609. The reversal of 19204693561 is 16539640291.

The square root of 19204693561 is 138581.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 18284177961 + 920515600 = 135219^2 + 30340^2 .

It is not a de Polignac number, because 19204693561 - 2⁹ = 19204693049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19204693531) 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 in 2 ways as a sum of consecutive naturals, for example, 69291 + ... + 207871.

Almost surely, 2^19204693561 is an apocalyptic number.

19204693561 is the 138581-st square number.

19204693561 is the 69291-st centered octagonal number.

It is an amenable number.

19204693561 is a deficient number, since it is larger than the sum of its proper divisors (138582).

19204693561 is an frugal number, since it uses more digits than its factorization.

19204693561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277162 (or 138581 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 46.

The spelling of 19204693561 in words is "nineteen billion, two hundred four million, six hundred ninety-three thousand, five hundred sixty-one".