19431523609 has 3 divisors (see below), whose sum is σ = 19431663007. Its totient is φ = 19431384212.

The previous prime is 19431523603. The next prime is 19431523673. The reversal of 19431523609 is 90632513491.

It is a happy number.

The square root of 19431523609 is 139397.

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., 4112015625 + 15319507984 = 64125^2 + 123772^2 .

It is not a de Polignac number, because 19431523609 - 2¹¹ = 19431521561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19431523603) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 69699 + ... + 209095.

Almost surely, 2^19431523609 is an apocalyptic number.

19431523609 is the 139397-th square number.

19431523609 is the 69699-th centered octagonal number.

It is an amenable number.

19431523609 is a deficient number, since it is larger than the sum of its proper divisors (139398).

19431523609 is an frugal number, since it uses more digits than its factorization.

19431523609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278794 (or 139397 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 43.

The spelling of 19431523609 in words is "nineteen billion, four hundred thirty-one million, five hundred twenty-three thousand, six hundred nine".