231785820 has 192 divisors, whose sum is σ = 872847360. Its totient is φ = 49849344.

The previous prime is 231785783. The next prime is 231785831. The reversal of 231785820 is 28587132.

231785820 is a `hidden beast` number, since 2 + 3 + 1 + 78 + 582 + 0 = 666.

231785820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 62457 + ... + 66063.

It is an arithmetic number, because the mean of its divisors is an integer number (4546080).

Almost surely, 2^231785820 is an apocalyptic number.

231785820 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 231785820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (436423680).

231785820 is an abundant number, since it is smaller than the sum of its proper divisors (641061540).

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

231785820 is a wasteful number, since it uses less digits than its factorization.

231785820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3649 (or 3641 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 231785820 is about 15224.5137853397. The cubic root of 231785820 is about 614.2742181783.

The spelling of 231785820 in words is "two hundred thirty-one million, seven hundred eighty-five thousand, eight hundred twenty".