19728905 has 16 divisors (see below), whose sum is σ = 27243264. Its totient is φ = 13435200.

The previous prime is 19728901. The next prime is 19728911. The reversal of 19728905 is 50982791.

It is not a de Polignac number, because 19728905 - 2² = 19728901 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19728901) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3419 + ... + 7151.

It is an arithmetic number, because the mean of its divisors is an integer number (1702704).

Almost surely, 2^19728905 is an apocalyptic number.

It is an amenable number.

19728905 is a deficient number, since it is larger than the sum of its proper divisors (7514359).

19728905 is a wasteful number, since it uses less digits than its factorization.

19728905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3896.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 19728905 is about 4441.7232016415. The cubic root of 19728905 is about 270.2097364398.

The spelling of 19728905 in words is "nineteen million, seven hundred twenty-eight thousand, nine hundred five".