19905521208 has 16 divisors (see below), whose sum is σ = 49763803080. Its totient is φ = 6635173728.

The previous prime is 19905521201. The next prime is 19905521219. The reversal of 19905521208 is 80212550991.

It is a self number, because there is not a number n which added to its sum of digits gives 19905521208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19905521201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 414698335 + ... + 414698382.

Almost surely, 2^19905521208 is an apocalyptic number.

It is an amenable number.

19905521208 is an abundant number, since it is smaller than the sum of its proper divisors (29858281872).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19905521208 is a wasteful number, since it uses less digits than its factorization.

19905521208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829396726 (or 829396722 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 42.

The spelling of 19905521208 in words is "nineteen billion, nine hundred five million, five hundred twenty-one thousand, two hundred eight".