19129932721 has 3 divisors (see below), whose sum is σ = 19130071033. Its totient is φ = 19129794410.

The previous prime is 19129932709. The next prime is 19129932727. The reversal of 19129932721 is 12723992191.

The square root of 19129932721 is 138311.

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 is not a de Polignac number, because 19129932721 - 2¹⁵ = 19129899953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19129932727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 69156 + ... + 207466.

Almost surely, 2^19129932721 is an apocalyptic number.

19129932721 is the 138311-st square number.

19129932721 is the 69156-th centered octagonal number.

It is an amenable number.

19129932721 is a deficient number, since it is larger than the sum of its proper divisors (138312).

19129932721 is an frugal number, since it uses more digits than its factorization.

19129932721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276622 (or 138311 counting only the distinct ones).

The product of its digits is 122472, while the sum is 46.

The spelling of 19129932721 in words is "nineteen billion, one hundred twenty-nine million, nine hundred thirty-two thousand, seven hundred twenty-one".