18938683981 has 16 divisors (see below), whose sum is σ = 22110626304. Its totient is φ = 15883530624.

The previous prime is 18938683957. The next prime is 18938683993.

18938683981 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 18938683981 - 2¹⁵ = 18938651213 is a prime.

It is a super-2 number, since 2×18938683981² (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 (18938683681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2125171 + ... + 2134063.

It is an arithmetic number, because the mean of its divisors is an integer number (1381914144).

Almost surely, 2^18938683981 is an apocalyptic number.

It is an amenable number.

18938683981 is a deficient number, since it is larger than the sum of its proper divisors (3171942323).

18938683981 is an equidigital number, since it uses as much as digits as its factorization.

18938683981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15420.

The product of its digits is 17915904, while the sum is 64.

The spelling of 18938683981 in words is "eighteen billion, nine hundred thirty-eight million, six hundred eighty-three thousand, nine hundred eighty-one".