19728815 has 8 divisors (see below), whose sum is σ = 23861760. Its totient is φ = 15658272.

The previous prime is 19728811. The next prime is 19728829. The reversal of 19728815 is 51882791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19728815 - 2² = 19728811 is a prime.

It is a super-2 number, since 2×19728815² = 778452282608450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19728811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14900 + ... + 16169.

It is an arithmetic number, because the mean of its divisors is an integer number (2982720).

Almost surely, 2^19728815 is an apocalyptic number.

19728815 is a deficient number, since it is larger than the sum of its proper divisors (4132945).

19728815 is a wasteful number, since it uses less digits than its factorization.

19728815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31201.

The product of its digits is 40320, while the sum is 41.

The square root of 19728815 is about 4441.7130704268. The cubic root of 19728815 is about 270.2093255551.

The spelling of 19728815 in words is "nineteen million, seven hundred twenty-eight thousand, eight hundred fifteen".