181811838 has 64 divisors (see below), whose sum is σ = 428101632. Its totient is φ = 50941440.

The previous prime is 181811831. The next prime is 181811857. The reversal of 181811838 is 838118181.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 181811796 and 181811805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181811831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 38895 + ... + 43317.

It is an arithmetic number, because the mean of its divisors is an integer number (6689088).

Almost surely, 2^181811838 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181811838, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (214050816).

181811838 is an abundant number, since it is smaller than the sum of its proper divisors (246289794).

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

181811838 is a wasteful number, since it uses less digits than its factorization.

181811838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4489.

The product of its digits is 12288, while the sum is 39.

The square root of 181811838 is about 13483.7620121389. The cubic root of 181811838 is about 566.5097460923.

The spelling of 181811838 in words is "one hundred eighty-one million, eight hundred eleven thousand, eight hundred thirty-eight".