19928507569 has 4 divisors (see below), whose sum is σ = 19929146740. Its totient is φ = 19927868400.

The previous prime is 19928507551. The next prime is 19928507591. The reversal of 19928507569 is 96570582991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96570582991 = 107 ⋅902528813.

It can be written as a sum of positive squares in 2 ways, for example, as 15932750625 + 3995756944 = 126225^2 + 63212^2 .

It is a cyclic number.

It is not a de Polignac number, because 19928507569 - 2²³ = 19920118961 is a prime.

It is a super-2 number, since 2×19928507569² (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 (19928508569) 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 3 ways as a sum of consecutive naturals, for example, 270282 + ... + 336019.

It is an arithmetic number, because the mean of its divisors is an integer number (4982286685).

Almost surely, 2^19928507569 is an apocalyptic number.

It is an amenable number.

19928507569 is a deficient number, since it is larger than the sum of its proper divisors (639171).

19928507569 is an equidigital number, since it uses as much as digits as its factorization.

19928507569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639170.

The product of its (nonzero) digits is 12247200, while the sum is 61.

The spelling of 19928507569 in words is "nineteen billion, nine hundred twenty-eight million, five hundred seven thousand, five hundred sixty-nine".