133231220 has 54 divisors (see below), whose sum is σ = 293058402. Its totient is φ = 50876672.

The previous prime is 133231207. The next prime is 133231223. The reversal of 133231220 is 22132331.

It can be written as a sum of positive squares in 9 ways, for example, as 64705936 + 68525284 = 8044^2 + 8278^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133231223) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1496936 + ... + 1497024.

Almost surely, 2^133231220 is an apocalyptic number.

133231220 is a gapful number since it is divisible by the number (10) 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 133231220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146529201).

133231220 is an abundant number, since it is smaller than the sum of its proper divisors (159827182).

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

133231220 is an equidigital number, since it uses as much as digits as its factorization.

133231220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245 (or 125 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 133231220 is about 11542.5828998539. The cubic root of 133231220 is about 510.7425042706.

Adding to 133231220 its reverse (22132331), we get a palindrome (155363551).

The spelling of 133231220 in words is "one hundred thirty-three million, two hundred thirty-one thousand, two hundred twenty".