19943840709 has 32 divisors (see below), whose sum is σ = 31903401600. Its totient is φ = 12240668160.

The previous prime is 19943840689. The next prime is 19943840723. The reversal of 19943840709 is 90704834991.

19943840709 is a `hidden beast` number, since 199 + 4 + 384 + 0 + 70 + 9 = 666.

It is not a de Polignac number, because 19943840709 - 2²⁴ = 19927063493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19943840759) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58069 + ... + 207989.

It is an arithmetic number, because the mean of its divisors is an integer number (996981300).

Almost surely, 2^19943840709 is an apocalyptic number.

It is an amenable number.

19943840709 is a deficient number, since it is larger than the sum of its proper divisors (11959560891).

19943840709 is a wasteful number, since it uses less digits than its factorization.

19943840709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150322 (or 150316 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 54.

The spelling of 19943840709 in words is "nineteen billion, nine hundred forty-three million, eight hundred forty thousand, seven hundred nine".