18847485789921 has 24 divisors (see below), whose sum is σ = 27475794305960. Its totient is φ = 12448861042176.

The previous prime is 18847485789841. The next prime is 18847485789941. The reversal of 18847485789921 is 12998758474881.

18847485789921 is a `hidden beast` number, since 1 + 8 + 8 + 47 + 485 + 7 + 8 + 9 + 92 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 13324609783521 + 5522876006400 = 3650289^2 + 2350080^2 .

It is not a de Polignac number, because 18847485789921 - 2¹⁹ = 18847485265633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18847485789941) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 13805151 + ... + 15108843.

Almost surely, 2^{18847485789921} is an apocalyptic number.

It is an amenable number.

18847485789921 is a deficient number, since it is larger than the sum of its proper divisors (8628308516039).

18847485789921 is a wasteful number, since it uses less digits than its factorization.

18847485789921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1318545 (or 1318542 counting only the distinct ones).

The product of its digits is 2601123840, while the sum is 81.

The spelling of 18847485789921 in words is "eighteen trillion, eight hundred forty-seven billion, four hundred eighty-five million, seven hundred eighty-nine thousand, nine hundred twenty-one".