19993409 has 4 divisors (see below), whose sum is σ = 20458416. Its totient is φ = 19528404.

The previous prime is 19993381. The next prime is 19993447. The reversal of 19993409 is 90439991.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19993409 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 19993409.

It is not an unprimeable number, because it can be changed into a prime (19993469) 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, 232439 + ... + 232524.

It is an arithmetic number, because the mean of its divisors is an integer number (5114604).

Almost surely, 2^19993409 is an apocalyptic number.

It is an amenable number.

19993409 is a deficient number, since it is larger than the sum of its proper divisors (465007).

19993409 is an equidigital number, since it uses as much as digits as its factorization.

19993409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465006.

The product of its (nonzero) digits is 78732, while the sum is 44.

The square root of 19993409 is about 4471.3989980766. The cubic root of 19993409 is about 271.4119405059.

It can be divided in two parts, 19993 and 409, that added together give a palindrome (20402).

The spelling of 19993409 in words is "nineteen million, nine hundred ninety-three thousand, four hundred nine".