19709842 has 4 divisors (see below), whose sum is σ = 29564766. Its totient is φ = 9854920.

The previous prime is 19709839. The next prime is 19709843. The reversal of 19709842 is 24890791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24890791 = 1471 ⋅16921.

It can be written as a sum of positive squares in only one way, i.e., 10106041 + 9603801 = 3179^2 + 3099^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 19709795 and 19709804.

It is not an unprimeable number, because it can be changed into a prime (19709843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4927459 + ... + 4927462.

Almost surely, 2^19709842 is an apocalyptic number.

19709842 is a deficient number, since it is larger than the sum of its proper divisors (9854924).

19709842 is an equidigital number, since it uses as much as digits as its factorization.

19709842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9854923.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 19709842 is about 4439.5767816313. The cubic root of 19709842 is about 270.1226785900.

The spelling of 19709842 in words is "nineteen million, seven hundred nine thousand, eight hundred forty-two".