17981388243 has 144 divisors (see below), whose sum is σ = 33338716320. Its totient is φ = 9309396096.

The previous prime is 17981388241. The next prime is 17981388301. The reversal of 17981388243 is 34288318971.

It is a happy number.

17981388243 is a `hidden beast` number, since 17 + 9 + 8 + 1 + 388 + 243 = 666.

It is not a de Polignac number, because 17981388243 - 2¹ = 17981388241 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 17981388243.

It is not an unprimeable number, because it can be changed into a prime (17981388241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 64914621 + ... + 64914897.

Almost surely, 2^17981388243 is an apocalyptic number.

17981388243 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

17981388243 is a deficient number, since it is larger than the sum of its proper divisors (15357328077).

17981388243 is a wasteful number, since it uses less digits than its factorization.

17981388243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403 (or 367 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 54.

It can be divided in two parts, 1798 and 1388243, that added together give a square (1390041 = 1179²).

The spelling of 17981388243 in words is "seventeen billion, nine hundred eighty-one million, three hundred eighty-eight thousand, two hundred forty-three".