231181920 has 144 divisors (see below), whose sum is σ = 810416880. Its totient is φ = 59968512.

The previous prime is 231181891. The next prime is 231181921. The reversal of 231181920 is 29181132.

231181920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231181921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 51111 + ... + 55449.

It is an arithmetic number, because the mean of its divisors is an integer number (5627895).

Almost surely, 2^231181920 is an apocalyptic number.

231181920 is a gapful number since it is divisible by the number (20) 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 231181920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (405208440).

231181920 is an abundant number, since it is smaller than the sum of its proper divisors (579234960).

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

231181920 is a wasteful number, since it uses less digits than its factorization.

231181920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4397 (or 4386 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 231181920 is about 15204.6677043597. The cubic root of 231181920 is about 613.7402728938.

The spelling of 231181920 in words is "two hundred thirty-one million, one hundred eighty-one thousand, nine hundred twenty".