181336644 has 60 divisors (see below), whose sum is σ = 475675200. Its totient is φ = 60238512.

The previous prime is 181336643. The next prime is 181336693. The reversal of 181336644 is 446633181.

It is a happy number.

181336644 is a `hidden beast` number, since 1 + 8 + 1 + 3 + 3 + 6 + 644 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 181336599 and 181336608.

It is not an unprimeable number, because it can be changed into a prime (181336643) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 115537 + ... + 117095.

It is an arithmetic number, because the mean of its divisors is an integer number (7927920).

Almost surely, 2^181336644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181336644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (237837600).

181336644 is an abundant number, since it is smaller than the sum of its proper divisors (294338556).

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

181336644 is a wasteful number, since it uses less digits than its factorization.

181336644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1934 (or 1923 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 181336644 is about 13466.1295107392. The cubic root of 181336644 is about 566.0157611930.

The spelling of 181336644 in words is "one hundred eighty-one million, three hundred thirty-six thousand, six hundred forty-four".