18936688663981 has 16 divisors (see below), whose sum is σ = 20681773560000. Its totient is φ = 17195536500480.

The previous prime is 18936688663969. The next prime is 18936688663987.

18936688663981 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 18936688663981 - 2³⁷ = 18799249710509 is a prime.

It is a super-2 number, since 2×18936688663981² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18936688663895 and 18936688663904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18936688663987) 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 15 ways as a sum of consecutive naturals, for example, 82126405 + ... + 82356661.

It is an arithmetic number, because the mean of its divisors is an integer number (1292610847500).

Almost surely, 2^{18936688663981} is an apocalyptic number.

18936688663981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18936688663981 is a deficient number, since it is larger than the sum of its proper divisors (1745084896019).

18936688663981 is a wasteful number, since it uses less digits than its factorization.

18936688663981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238764.

The product of its digits is 3869835264, while the sum is 82.

The spelling of 18936688663981 in words is "eighteen trillion, nine hundred thirty-six billion, six hundred eighty-eight million, six hundred sixty-three thousand, nine hundred eighty-one".