18754687981 has 4 divisors (see below), whose sum is σ = 18756175932. Its totient is φ = 18753200032.

The previous prime is 18754687951. The next prime is 18754687999. The reversal of 18754687981 is 18978645781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18978645781 = 659 ⋅28799159.

It can be written as a sum of positive squares in 2 ways, for example, as 17362278756 + 1392409225 = 131766^2 + 37315^2 .

It is a cyclic number.

It is not a de Polignac number, because 18754687981 - 2⁵ = 18754687949 is a prime.

It is a super-2 number, since 2×18754687981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18754687901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 724906 + ... + 750331.

It is an arithmetic number, because the mean of its divisors is an integer number (4689043983).

Almost surely, 2^18754687981 is an apocalyptic number.

It is an amenable number.

18754687981 is a deficient number, since it is larger than the sum of its proper divisors (1487951).

18754687981 is a wasteful number, since it uses less digits than its factorization.

18754687981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1487950.

The product of its digits is 27095040, while the sum is 64.

The spelling of 18754687981 in words is "eighteen billion, seven hundred fifty-four million, six hundred eighty-seven thousand, nine hundred eighty-one".