133531218 has 24 divisors (see below), whose sum is σ = 289551756. Its totient is φ = 44474400.

The previous prime is 133531207. The next prime is 133531231. The reversal of 133531218 is 812135331.

133531218 is a `hidden beast` number, since 1 + 335 + 312 + 18 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 132779529 + 751689 = 11523^2 + 867^2 .

It is a junction number, because it is equal to n+sod(n) for n = 133531191 and 133531200.

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, 29208 + ... + 33468.

Almost surely, 2^133531218 is an apocalyptic number.

133531218 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

133531218 is an abundant number, since it is smaller than the sum of its proper divisors (156020538).

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

133531218 is a wasteful number, since it uses less digits than its factorization.

133531218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6010 (or 6007 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 133531218 is about 11555.5708643061. The cubic root of 133531218 is about 511.1255648122.

Adding to 133531218 its reverse (812135331), we get a palindrome (945666549).

The spelling of 133531218 in words is "one hundred thirty-three million, five hundred thirty-one thousand, two hundred eighteen".