19980104347921 has 3 divisors (see below), whose sum is σ = 19980108817833. Its totient is φ = 19980099878010.

The previous prime is 19980104347901. The next prime is 19980104347949. The reversal of 19980104347921 is 12974340108991.

It is a happy number.

The square root of 19980104347921 is 4469911.

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 19980104347921 - 2¹⁹ = 19980103823633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19980104347901) 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, 2234956 + ... + 6704866.

It is an arithmetic number, because the mean of its divisors is an integer number (6660036272611).

Almost surely, 2^{19980104347921} is an apocalyptic number.

19980104347921 is the 4469911-st square number.

19980104347921 is the 2234956-th centered octagonal number.

It is an amenable number.

19980104347921 is a deficient number, since it is larger than the sum of its proper divisors (4469912).

19980104347921 is an frugal number, since it uses more digits than its factorization.

19980104347921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8939822 (or 4469911 counting only the distinct ones).

The product of its (nonzero) digits is 3919104, while the sum is 58.

The spelling of 19980104347921 in words is "nineteen trillion, nine hundred eighty billion, one hundred four million, three hundred forty-seven thousand, nine hundred twenty-one".