19917109305 has 64 divisors (see below), whose sum is σ = 37912665600. Its totient is φ = 9885173760.

The previous prime is 19917109217. The next prime is 19917109379. The reversal of 19917109305 is 50390171991.

It is a happy number.

It is not a de Polignac number, because 19917109305 - 2¹⁵ = 19917076537 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 155500 + ... + 253010.

It is an arithmetic number, because the mean of its divisors is an integer number (592385400).

Almost surely, 2^19917109305 is an apocalyptic number.

19917109305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19917109305 is a deficient number, since it is larger than the sum of its proper divisors (17995556295).

19917109305 is a wasteful number, since it uses less digits than its factorization.

19917109305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97631 (or 97625 counting only the distinct ones).

The product of its (nonzero) digits is 76545, while the sum is 45.

The spelling of 19917109305 in words is "nineteen billion, nine hundred seventeen million, one hundred nine thousand, three hundred five".