133155521 has 4 divisors (see below), whose sum is σ = 133581252. Its totient is φ = 132729792.

The previous prime is 133155511. The next prime is 133155523. The reversal of 133155521 is 125551331.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 125551331 = 4007 ⋅31333.

It can be written as a sum of positive squares in 2 ways, for example, as 9834496 + 123321025 = 3136^2 + 11105^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-133155521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133155523) 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 3 ways as a sum of consecutive naturals, for example, 212396 + ... + 213021.

It is an arithmetic number, because the mean of its divisors is an integer number (33395313).

Almost surely, 2^133155521 is an apocalyptic number.

It is an amenable number.

133155521 is a deficient number, since it is larger than the sum of its proper divisors (425731).

133155521 is an equidigital number, since it uses as much as digits as its factorization.

133155521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425730.

The product of its digits is 2250, while the sum is 26.

The square root of 133155521 is about 11539.3033151920. The cubic root of 133155521 is about 510.6457551214.

The spelling of 133155521 in words is "one hundred thirty-three million, one hundred fifty-five thousand, five hundred twenty-one".