231323220 has 36 divisors (see below), whose sum is σ = 701680980. Its totient is φ = 61686144.

The previous prime is 231323219. The next prime is 231323231. The reversal of 231323220 is 22323132.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 89189136 + 142134084 = 9444^2 + 11922^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×231323220² = 107020864222336800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 231323193 and 231323202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 642385 + ... + 642744.

Almost surely, 2^231323220 is an apocalyptic number.

231323220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

231323220 is an abundant number, since it is smaller than the sum of its proper divisors (470357760).

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

231323220 is a wasteful number, since it uses less digits than its factorization.

231323220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1285144 (or 1285139 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 18.

The square root of 231323220 is about 15209.3135939792. The cubic root of 231323220 is about 613.8652882039.

Adding to 231323220 its reverse (22323132), we get a palindrome (253646352).

The spelling of 231323220 in words is "two hundred thirty-one million, three hundred twenty-three thousand, two hundred twenty".