181661544 has 96 divisors (see below), whose sum is σ = 517308480. Its totient is φ = 57480192.

The previous prime is 181661509. The next prime is 181661561. The reversal of 181661544 is 445166181.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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 = 181661499 and 181661508.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 269592 + ... + 270264.

It is an arithmetic number, because the mean of its divisors is an integer number (5388630).

Almost surely, 2^181661544 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 181661544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (258654240).

181661544 is an abundant number, since it is smaller than the sum of its proper divisors (335646936).

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

181661544 is a wasteful number, since it uses less digits than its factorization.

181661544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 871 (or 864 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 181661544 is about 13478.1877120034. The cubic root of 181661544 is about 566.3536020836.

The spelling of 181661544 in words is "one hundred eighty-one million, six hundred sixty-one thousand, five hundred forty-four".