18724221128 has 36 divisors (see below), whose sum is σ = 35533140945. Its totient is φ = 9250064800.

The previous prime is 18724221127. The next prime is 18724221149. The reversal of 18724221128 is 82112242781.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 12996456004 + 5727765124 = 114002^2 + 75682^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=96758.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18724221091 and 18724221100.

It is not an unprimeable number, because it can be changed into a prime (18724221127) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 39089993 + ... + 39090471.

Almost surely, 2^18724221128 is an apocalyptic number.

It is an amenable number.

18724221128 is a deficient number, since it is larger than the sum of its proper divisors (16808919817).

18724221128 is an frugal number, since it uses more digits than its factorization.

18724221128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166 (or 582 counting only the distinct ones).

The product of its digits is 28672, while the sum is 38.

The spelling of 18724221128 in words is "eighteen billion, seven hundred twenty-four million, two hundred twenty-one thousand, one hundred twenty-eight".