19712609 has 4 divisors (see below), whose sum is σ = 22528704. Its totient is φ = 16896516.

The previous prime is 19712603. The next prime is 19712611. The reversal of 19712609 is 90621791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 90621791 = 13 ⋅6970907.

It is not a de Polignac number, because 19712609 - 2⁴ = 19712593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19712603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1408037 + ... + 1408050.

It is an arithmetic number, because the mean of its divisors is an integer number (5632176).

Almost surely, 2^19712609 is an apocalyptic number.

It is an amenable number.

19712609 is a deficient number, since it is larger than the sum of its proper divisors (2816095).

19712609 is an equidigital number, since it uses as much as digits as its factorization.

19712609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2816094.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 19712609 is about 4439.8883994983. Note that the first 3 decimals coincide. The cubic root of 19712609 is about 270.1353185438.

The spelling of 19712609 in words is "nineteen million, seven hundred twelve thousand, six hundred nine".