19888109 has 2 divisors, whose sum is σ = 19888110. Its totient is φ = 19888108.

The previous prime is 19888087. The next prime is 19888111. The reversal of 19888109 is 90188891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16630084 + 3258025 = 4078^2 + 1805^2 .

It is a cyclic number.

It is not a de Polignac number, because 19888109 - 2⁸ = 19887853 is a prime.

Together with 19888111, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19888109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19888189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9944054 + 9944055.

It is an arithmetic number, because the mean of its divisors is an integer number (9944055).

Almost surely, 2^19888109 is an apocalyptic number.

It is an amenable number.

19888109 is a deficient number, since it is larger than the sum of its proper divisors (1).

19888109 is an equidigital number, since it uses as much as digits as its factorization.

19888109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 44.

The square root of 19888109 is about 4459.6086151141. The cubic root of 19888109 is about 270.9346165616.

The spelling of 19888109 in words is "nineteen million, eight hundred eighty-eight thousand, one hundred nine".