18513816981 has 8 divisors (see below), whose sum is σ = 26929188384. Its totient is φ = 11220495120.

The previous prime is 18513816973. The next prime is 18513817001. The reversal of 18513816981 is 18961831581.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18513816981 - 2³ = 18513816973 is a prime.

It is a super-2 number, since 2×18513816981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18513816941) 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 7 ways as a sum of consecutive naturals, for example, 280512346 + ... + 280512411.

It is an arithmetic number, because the mean of its divisors is an integer number (3366148548).

Almost surely, 2^18513816981 is an apocalyptic number.

18513816981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18513816981 is a deficient number, since it is larger than the sum of its proper divisors (8415371403).

18513816981 is a wasteful number, since it uses less digits than its factorization.

18513816981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561024771.

The product of its digits is 414720, while the sum is 51.

The spelling of 18513816981 in words is "eighteen billion, five hundred thirteen million, eight hundred sixteen thousand, nine hundred eighty-one".