19908363409 has 27 divisors (see below), whose sum is σ = 22276950843. Its totient is φ = 17778222000.

The previous prime is 19908363313. The next prime is 19908363421. The reversal of 19908363409 is 90436380991.

The square root of 19908363409 is 141097.

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., 19127719809 + 780643600 = 138303^2 + 27940^2 .

It is not a de Polignac number, because 19908363409 - 2⁹ = 19908362897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19908363109) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 156758704 + ... + 156758830.

Almost surely, 2^19908363409 is an apocalyptic number.

19908363409 is the 141097-th square number.

19908363409 is the 70549-th centered octagonal number.

It is an amenable number.

19908363409 is a deficient number, since it is larger than the sum of its proper divisors (2368587434).

19908363409 is an equidigital number, since it uses as much as digits as its factorization.

19908363409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478 (or 239 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 52.

The spelling of 19908363409 in words is "nineteen billion, nine hundred eight million, three hundred sixty-three thousand, four hundred nine".