133688221 has 6 divisors (see below), whose sum is σ = 142015130. Its totient is φ = 125823936.

The previous prime is 133688197. The next prime is 133688227. The reversal of 133688221 is 122886331.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 83064996 + 50623225 = 9114^2 + 7115^2 .

It is not a de Polignac number, because 133688221 - 2⁵ = 133688189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133688227) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 231006 + ... + 231583.

Almost surely, 2^133688221 is an apocalyptic number.

It is an amenable number.

133688221 is a deficient number, since it is larger than the sum of its proper divisors (8326909).

133688221 is an equidigital number, since it uses as much as digits as its factorization.

133688221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 462623 (or 462606 counting only the distinct ones).

The product of its digits is 13824, while the sum is 34.

The square root of 133688221 is about 11562.3622586390. The cubic root of 133688221 is about 511.3258096623.

The spelling of 133688221 in words is "one hundred thirty-three million, six hundred eighty-eight thousand, two hundred twenty-one".