133305521 has 4 divisors (see below), whose sum is σ = 134278692. Its totient is φ = 132332352.

The previous prime is 133305511. The next prime is 133305533. The reversal of 133305521 is 125503331.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 76755121 + 56550400 = 8761^2 + 7520^2 .

It is a cyclic number.

It is not a de Polignac number, because 133305521 - 2⁶ = 133305457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133305511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 486380 + ... + 486653.

It is an arithmetic number, because the mean of its divisors is an integer number (33569673).

Almost surely, 2^133305521 is an apocalyptic number.

It is an amenable number.

133305521 is a deficient number, since it is larger than the sum of its proper divisors (973171).

133305521 is an equidigital number, since it uses as much as digits as its factorization.

133305521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 973170.

The product of its (nonzero) digits is 1350, while the sum is 23.

The square root of 133305521 is about 11545.8010116232. The cubic root of 133305521 is about 510.8374310366.

Adding to 133305521 its reverse (125503331), we get a palindrome (258808852).

The spelling of 133305521 in words is "one hundred thirty-three million, three hundred five thousand, five hundred twenty-one".