19963569099721 has 27 divisors (see below), whose sum is σ = 22339199497383. Its totient is φ = 17831852728560.

The previous prime is 19963569099637. The next prime is 19963569099811. The reversal of 19963569099721 is 12799096536991.

It is a happy number.

The square root of 19963569099721 is 4468061.

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

It can be written as a sum of positive squares in only one way, i.e., 2953190695225 + 17010378404496 = 1718485^2 + 4124364^2 .

It is a de Polignac number, because none of the positive numbers 2^k-19963569099721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19963569099421) 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 26 ways as a sum of consecutive naturals, for example, 1800623040 + ... + 1800634126.

Almost surely, 2^{19963569099721} is an apocalyptic number.

19963569099721 is the 4468061-st square number.

19963569099721 is the 2234031-st centered octagonal number.

It is an amenable number.

19963569099721 is a deficient number, since it is larger than the sum of its proper divisors (2375630397662).

19963569099721 is an frugal number, since it uses more digits than its factorization.

19963569099721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22262 (or 11131 counting only the distinct ones).

The product of its (nonzero) digits is 446410440, while the sum is 76.

The spelling of 19963569099721 in words is "nineteen trillion, nine hundred sixty-three billion, five hundred sixty-nine million, ninety-nine thousand, seven hundred twenty-one".