19690409 has 4 divisors (see below), whose sum is σ = 19699716. Its totient is φ = 19681104.

The previous prime is 19690399. The next prime is 19690417. The reversal of 19690409 is 90409691.

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, and also an emirpimes, since its reverse is a distinct semiprime: 90409691 = 1787 ⋅50593.

It can be written as a sum of positive squares in 2 ways, for example, as 11833600 + 7856809 = 3440^2 + 2803^2 .

It is a cyclic number.

It is not a de Polignac number, because 19690409 - 2⁴ = 19690393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19690459) 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 3 ways as a sum of consecutive naturals, for example, 227 + ... + 6279.

It is an arithmetic number, because the mean of its divisors is an integer number (4924929).

Almost surely, 2^19690409 is an apocalyptic number.

It is an amenable number.

19690409 is a deficient number, since it is larger than the sum of its proper divisors (9307).

19690409 is an equidigital number, since it uses as much as digits as its factorization.

19690409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9306.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 19690409 is about 4437.3876323801. The cubic root of 19690409 is about 270.0338732079.

The spelling of 19690409 in words is "nineteen million, six hundred ninety thousand, four hundred nine".