19828709 has 4 divisors (see below), whose sum is σ = 19837740. Its totient is φ = 19819680.

The previous prime is 19828703. The next prime is 19828727. The reversal of 19828709 is 90782891.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15626209 + 4202500 = 3953^2 + 2050^2 .

It is a cyclic number.

It is not a de Polignac number, because 19828709 - 2⁴ = 19828693 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 19828709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19828703) 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, 1139 + ... + 6399.

It is an arithmetic number, because the mean of its divisors is an integer number (4959435).

Almost surely, 2^19828709 is an apocalyptic number.

It is an amenable number.

19828709 is a deficient number, since it is larger than the sum of its proper divisors (9031).

19828709 is an equidigital number, since it uses as much as digits as its factorization.

19828709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9030.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 19828709 is about 4452.9438577193. The cubic root of 19828709 is about 270.6646132633.

The spelling of 19828709 in words is "nineteen million, eight hundred twenty-eight thousand, seven hundred nine".