19797809 has 8 divisors (see below), whose sum is σ = 21639168. Its totient is φ = 18031680.

The previous prime is 19797787. The next prime is 19797839. The reversal of 19797809 is 90879791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19797809 - 2²⁰ = 18749233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19797839) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18257 + ... + 19310.

It is an arithmetic number, because the mean of its divisors is an integer number (2704896).

Almost surely, 2^19797809 is an apocalyptic number.

It is an amenable number.

19797809 is a deficient number, since it is larger than the sum of its proper divisors (1841359).

19797809 is a wasteful number, since it uses less digits than its factorization.

19797809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37615.

The product of its (nonzero) digits is 285768, while the sum is 50.

The square root of 19797809 is about 4449.4728901298. The cubic root of 19797809 is about 270.5239437465.

The spelling of 19797809 in words is "nineteen million, seven hundred ninety-seven thousand, eight hundred nine".