231220420 has 12 divisors (see below), whose sum is σ = 485562924. Its totient is φ = 92488160.

The previous prime is 231220387. The next prime is 231220421. The reversal of 231220420 is 24022132.

It can be written as a sum of positive squares in 2 ways, for example, as 127057984 + 104162436 = 11272^2 + 10206^2 .

It is a junction number, because it is equal to n+sod(n) for n = 231220394 and 231220403.

It is not an unprimeable number, because it can be changed into a prime (231220421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5780491 + ... + 5780530.

It is an arithmetic number, because the mean of its divisors is an integer number (40463577).

Almost surely, 2^231220420 is an apocalyptic number.

231220420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

231220420 is an abundant number, since it is smaller than the sum of its proper divisors (254342504).

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

231220420 is a wasteful number, since it uses less digits than its factorization.

231220420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11561030 (or 11561028 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 231220420 is about 15205.9337102330. The cubic root of 231220420 is about 613.7743408534.

Adding to 231220420 its reverse (24022132), we get a palindrome (255242552).

The spelling of 231220420 in words is "two hundred thirty-one million, two hundred twenty thousand, four hundred twenty".