19840919873 has 4 divisors (see below), whose sum is σ = 19854576468. Its totient is φ = 19827263280.

The previous prime is 19840919869. The next prime is 19840919881. The reversal of 19840919873 is 37891904891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37891904891 = 317 ⋅119532823.

It can be written as a sum of positive squares in 2 ways, for example, as 19676233984 + 164685889 = 140272^2 + 12833^2 .

It is a cyclic number.

It is not a de Polignac number, because 19840919873 - 2² = 19840919869 is a prime.

It is a super-2 number, since 2×19840919873² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19840919573) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6826118 + ... + 6829023.

It is an arithmetic number, because the mean of its divisors is an integer number (4963644117).

Almost surely, 2^19840919873 is an apocalyptic number.

It is an amenable number.

19840919873 is a deficient number, since it is larger than the sum of its proper divisors (13656595).

19840919873 is a wasteful number, since it uses less digits than its factorization.

19840919873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13656594.

The product of its (nonzero) digits is 3919104, while the sum is 59.

The spelling of 19840919873 in words is "nineteen billion, eight hundred forty million, nine hundred nineteen thousand, eight hundred seventy-three".