181920 has 48 divisors (see below), whose sum is σ = 574560. Its totient is φ = 48384.

The previous prime is 181919. The next prime is 181927. The reversal of 181920 is 29181.

It is a tau number, because it is divible by the number of its divisors (48).

It is not an unprimeable number, because it can be changed into a prime (181927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291 + ... + 669.

It is an arithmetic number, because the mean of its divisors is an integer number (11970).

2¹⁸¹⁹²⁰ is an apocalyptic number.

181920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (287280).

181920 is an abundant number, since it is smaller than the sum of its proper divisors (392640).

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

181920 is a wasteful number, since it uses less digits than its factorization.

181920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397 (or 389 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 181920 is about 426.5208084021. The cubic root of 181920 is about 56.6622064925.

The spelling of 181920 in words is "one hundred eighty-one thousand, nine hundred twenty".