18728478722 has 6 divisors (see below), whose sum is σ = 28093008393. Its totient is φ = 9364142592.

The previous prime is 18728478707. The next prime is 18728478751. The reversal of 18728478722 is 22787482781.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18727648801 + 829921 = 136849^2 + 911^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=96769.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 145154 + ... + 241922.

Almost surely, 2^18728478722 is an apocalyptic number.

18728478722 is a deficient number, since it is larger than the sum of its proper divisors (9364529671).

18728478722 is an frugal number, since it uses more digits than its factorization.

18728478722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193540 (or 96771 counting only the distinct ones).

The product of its digits is 5619712, while the sum is 56.

The spelling of 18728478722 in words is "eighteen billion, seven hundred twenty-eight million, four hundred seventy-eight thousand, seven hundred twenty-two".