19903581363649 has 9 divisors (see below), whose sum is σ = 19933852883427. Its totient is φ = 19873355764824.

The previous prime is 19903581363637. The next prime is 19903581363691. The reversal of 19903581363649 is 94636318530991.

The square root of 19903581363649 is 4461343.

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., 3907837080625 + 15995744283024 = 1976825^2 + 3999468^2 .

It is not a de Polignac number, because 19903581363649 - 2³⁹ = 19353825549761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19903581363749) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3296929459 + ... + 3296935495.

It is an arithmetic number, because the mean of its divisors is an integer number (2214872542603).

Almost surely, 2^{19903581363649} is an apocalyptic number.

19903581363649 is the 4461343-rd square number.

19903581363649 is the 2230672-nd centered octagonal number.

It is an amenable number.

19903581363649 is a deficient number, since it is larger than the sum of its proper divisors (30271519778).

19903581363649 is an frugal number, since it uses more digits than its factorization.

19903581363649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13552 (or 6776 counting only the distinct ones).

The product of its (nonzero) digits is 113374080, while the sum is 67.

The spelling of 19903581363649 in words is "nineteen trillion, nine hundred three billion, five hundred eighty-one million, three hundred sixty-three thousand, six hundred forty-nine".