8918138881 has 4 divisors (see below), whose sum is σ = 8918342100. Its totient is φ = 8917935664.

The previous prime is 8918138861. The next prime is 8918138941. The reversal of 8918138881 is 1888318198.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8675059600 + 243079281 = 93140^2 + 15591^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8918138881 is a prime.

It is a super-2 number, since 2×8918138881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8918138861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5446 + ... + 133663.

It is an arithmetic number, because the mean of its divisors is an integer number (2229585525).

It is a Proth number, since it is equal to 8505 ⋅ 2²⁰ + 1 and 8505 < 2²⁰.

Almost surely, 2^8918138881 is an apocalyptic number.

It is an amenable number.

8918138881 is a deficient number, since it is larger than the sum of its proper divisors (203219).

8918138881 is a wasteful number, since it uses less digits than its factorization.

8918138881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203218.

The product of its digits is 884736, while the sum is 55.

The square root of 8918138881 is about 94435.8982643783. The cubic root of 8918138881 is about 2073.7580127277.

The spelling of 8918138881 in words is "eight billion, nine hundred eighteen million, one hundred thirty-eight thousand, eight hundred eighty-one".