19952650651921 has 15 divisors (see below), whose sum is σ = 21616131155613. Its totient is φ = 18417134544120.

The previous prime is 19952650651883. The next prime is 19952650651937. The reversal of 19952650651921 is 12915605625991.

The square root of 19952650651921 is 4466839.

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

It can be written as a sum of positive squares in 2 ways, for example, as 9892842893521 + 10059807758400 = 3145289^2 + 3171720^2 .

It is not a de Polignac number, because 19952650651921 - 2¹¹ = 19952650649873 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19952650651921.

It is not an unprimeable number, because it can be changed into a prime (19952650651991) 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 14 ways as a sum of consecutive naturals, for example, 754882576 + ... + 754909006.

Almost surely, 2^{19952650651921} is an apocalyptic number.

19952650651921 is the 4466839-th square number.

19952650651921 is the 2233420-th centered octagonal number.

It is an amenable number.

19952650651921 is a deficient number, since it is larger than the sum of its proper divisors (1663480503692).

19952650651921 is an frugal number, since it uses more digits than its factorization.

19952650651921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52914 (or 26444 counting only the distinct ones).

The product of its (nonzero) digits is 13122000, while the sum is 61.

The spelling of 19952650651921 in words is "nineteen trillion, nine hundred fifty-two billion, six hundred fifty million, six hundred fifty-one thousand, nine hundred twenty-one".