19991840068 has 24 divisors (see below), whose sum is σ = 35358155000. Its totient is φ = 9889579008.

The previous prime is 19991840023. The next prime is 19991840087. The reversal of 19991840068 is 86004819991.

It can be written as a sum of positive squares in 4 ways, for example, as 2459961604 + 17531878464 = 49598^2 + 132408^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1502308 + ... + 1515556.

Almost surely, 2^19991840068 is an apocalyptic number.

It is an amenable number.

19991840068 is a deficient number, since it is larger than the sum of its proper divisors (15366314932).

19991840068 is a wasteful number, since it uses less digits than its factorization.

19991840068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17239 (or 17237 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 55.

The spelling of 19991840068 in words is "nineteen billion, nine hundred ninety-one million, eight hundred forty thousand, sixty-eight".