231135220 has 24 divisors (see below), whose sum is σ = 502122600. Its totient is φ = 89265792.

The previous prime is 231135199. The next prime is 231135239. The reversal of 231135220 is 22531132.

It can be written as a sum of positive squares in 4 ways, for example, as 3849444 + 227285776 = 1962^2 + 15076^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 198675 + ... + 199834.

It is an arithmetic number, because the mean of its divisors is an integer number (20921775).

Almost surely, 2^231135220 is an apocalyptic number.

231135220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

231135220 is an abundant number, since it is smaller than the sum of its proper divisors (270987380).

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

231135220 is a wasteful number, since it uses less digits than its factorization.

231135220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398547 (or 398545 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 231135220 is about 15203.1319141814. The cubic root of 231135220 is about 613.6989438243.

Adding to 231135220 its reverse (22531132), we get a palindrome (253666352).

The spelling of 231135220 in words is "two hundred thirty-one million, one hundred thirty-five thousand, two hundred twenty".