19905541569 has 27 divisors (see below), whose sum is σ = 29054539969. Its totient is φ = 13132377960.

The previous prime is 19905541561. The next prime is 19905541637. The reversal of 19905541569 is 96514550991.

The square root of 19905541569 is 141087.

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

19905541569 is a `hidden beast` number, since 1 + 9 + 90 + 5 + 541 + 5 + 6 + 9 = 666.

It is not a de Polignac number, because 19905541569 - 2³ = 19905541561 is a prime.

It is a super-2 number, since 2×19905541569² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19905541561) 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 26 ways as a sum of consecutive naturals, for example, 55447012 + ... + 55447370.

Almost surely, 2^19905541569 is an apocalyptic number.

19905541569 is the 141087-th square number.

19905541569 is the 70544-th centered octagonal number.

It is an amenable number.

19905541569 is a deficient number, since it is larger than the sum of its proper divisors (9148998400).

19905541569 is an frugal number, since it uses more digits than its factorization.

19905541569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 986 (or 493 counting only the distinct ones).

The product of its (nonzero) digits is 2187000, while the sum is 54.

The spelling of 19905541569 in words is "nineteen billion, nine hundred five million, five hundred forty-one thousand, five hundred sixty-nine".