19988309 has 8 divisors (see below), whose sum is σ = 22069152. Its totient is φ = 17951440.

The previous prime is 19988291. The next prime is 19988321. The reversal of 19988309 is 90388991.

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 19988309 - 2¹² = 19984213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19988359) 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, 10034 + ... + 11859.

It is an arithmetic number, because the mean of its divisors is an integer number (2758644).

Almost surely, 2^19988309 is an apocalyptic number.

It is an amenable number.

19988309 is a deficient number, since it is larger than the sum of its proper divisors (2080843).

19988309 is a wasteful number, since it uses less digits than its factorization.

19988309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21987.

The product of its (nonzero) digits is 139968, while the sum is 47.

The square root of 19988309 is about 4470.8286703921. The cubic root of 19988309 is about 271.3888609232.

The spelling of 19988309 in words is "nineteen million, nine hundred eighty-eight thousand, three hundred nine".