81801108 has 18 divisors (see below), whose sum is σ = 206775114. Its totient is φ = 27267024.

The previous prime is 81801107. The next prime is 81801143. The reversal of 81801108 is 80110818.

It can be written as a sum of positive squares in only one way, i.e., 56520324 + 25280784 = 7518^2 + 5028^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81801107) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1136091 + ... + 1136162.

Almost surely, 2^81801108 is an apocalyptic number.

It is an amenable number.

81801108 is an abundant number, since it is smaller than the sum of its proper divisors (124974006).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81801108 is a wasteful number, since it uses less digits than its factorization.

81801108 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2272263 (or 2272258 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 27.

The square root of 81801108 is about 9044.3964972794. The cubic root of 81801108 is about 434.0966111098.

The spelling of 81801108 in words is "eighty-one million, eight hundred one thousand, one hundred eight".