18981573318 has 16 divisors (see below), whose sum is σ = 42181274160. Its totient is φ = 6327191088.

The previous prime is 18981573307. The next prime is 18981573341. The reversal of 18981573318 is 81337518981.

It is a happy number.

18981573318 is a `hidden beast` number, since 189 + 81 + 5 + 73 + 318 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54), and also a Moran number because the ratio is a prime number: 351510617 = 18981573318 / (1 + 8 + 9 + 8 + 1 + 5 + 7 + 3 + 3 + 1 + 8).

It is a congruent number.

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, 175755255 + ... + 175755362.

It is an arithmetic number, because the mean of its divisors is an integer number (2636329635).

Almost surely, 2^18981573318 is an apocalyptic number.

18981573318 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18981573318 is an abundant number, since it is smaller than the sum of its proper divisors (23199700842).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18981573318 is a wasteful number, since it uses less digits than its factorization.

18981573318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351510628 (or 351510622 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 54.

The spelling of 18981573318 in words is "eighteen billion, nine hundred eighty-one million, five hundred seventy-three thousand, three hundred eighteen".