231820 has 24 divisors (see below), whose sum is σ = 496944. Its totient is φ = 90816.

The previous prime is 231809. The next prime is 231821. The reversal of 231820 is 28132.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 231794 and 231803.

It is not an unprimeable number, because it can be changed into a prime (231821) by changing a digit.

231820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1254 + ... + 1426.

It is an arithmetic number, because the mean of its divisors is an integer number (20706).

2²³¹⁸²⁰ is an apocalyptic number.

231820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

231820 is an abundant number, since it is smaller than the sum of its proper divisors (265124).

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

231820 is a wasteful number, since it uses less digits than its factorization.

231820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249 (or 247 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 231820 is about 481.4768945650. The cubic root of 231820 is about 61.4304411082.

Adding to 231820 its reverse (28132), we get a palindrome (259952).

It can be divided in two parts, 2318 and 20, that multiplied together give a triangular number (46360 = T₃₀₄).

The spelling of 231820 in words is "two hundred thirty-one thousand, eight hundred twenty".