133231221 has 24 divisors (see below), whose sum is σ = 196375296. Its totient is φ = 87026400.

The previous prime is 133231207. The next prime is 133231223. The reversal of 133231221 is 122132331.

133231221 is a `hidden beast` number, since 1 + 332 + 312 + 21 = 666.

It is not a de Polignac number, because 133231221 - 2⁹ = 133230709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 133231194 and 133231203.

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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 92916 + ... + 94338.

It is an arithmetic number, because the mean of its divisors is an integer number (8182304).

Almost surely, 2^133231221 is an apocalyptic number.

It is an amenable number.

133231221 is a deficient number, since it is larger than the sum of its proper divisors (63144075).

133231221 is a wasteful number, since it uses less digits than its factorization.

133231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1633 (or 1630 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 133231221 is about 11542.5829431718. The cubic root of 133231221 is about 510.7425055485.

Adding to 133231221 its reverse (122132331), we get a palindrome (255363552).

The spelling of 133231221 in words is "one hundred thirty-three million, two hundred thirty-one thousand, two hundred twenty-one".