19942409 has 4 divisors (see below), whose sum is σ = 20223360. Its totient is φ = 19661460.

The previous prime is 19942397. The next prime is 19942423. The reversal of 19942409 is 90424991.

It is a happy number.

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: 90424991 = 151 ⋅598841.

It is a cyclic number.

It is not a de Polignac number, because 19942409 - 2¹² = 19938313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19942499) 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, 140369 + ... + 140510.

It is an arithmetic number, because the mean of its divisors is an integer number (5055840).

Almost surely, 2^19942409 is an apocalyptic number.

It is an amenable number.

19942409 is a deficient number, since it is larger than the sum of its proper divisors (280951).

19942409 is an equidigital number, since it uses as much as digits as its factorization.

19942409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280950.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 19942409 is about 4465.6924435075. The cubic root of 19942409 is about 271.1809678012.

The spelling of 19942409 in words is "nineteen million, nine hundred forty-two thousand, four hundred nine".