181981944 has 64 divisors (see below), whose sum is σ = 517860000. Its totient is φ = 59178240.

The previous prime is 181981939. The next prime is 181981963. The reversal of 181981944 is 449189181.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 181981944.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1419 + ... + 19130.

Almost surely, 2^181981944 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 181981944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (258930000).

181981944 is an abundant number, since it is smaller than the sum of its proper divisors (335878056).

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

181981944 is a wasteful number, since it uses less digits than its factorization.

181981944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20605 (or 20595 counting only the distinct ones).

The product of its digits is 82944, while the sum is 45.

The square root of 181981944 is about 13490.0683467505. The cubic root of 181981944 is about 566.6863694803.

The spelling of 181981944 in words is "one hundred eighty-one million, nine hundred eighty-one thousand, nine hundred forty-four".