133520221 has 4 divisors (see below), whose sum is σ = 139325472. Its totient is φ = 127714972.

The previous prime is 133520207. The next prime is 133520237. The reversal of 133520221 is 122025331.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122025331 = 31 ⋅3936301.

It is a cyclic number.

It is not a de Polignac number, because 133520221 - 2⁹ = 133519709 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 (133520251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2902591 + ... + 2902636.

It is an arithmetic number, because the mean of its divisors is an integer number (34831368).

Almost surely, 2^133520221 is an apocalyptic number.

It is an amenable number.

133520221 is a deficient number, since it is larger than the sum of its proper divisors (5805251).

133520221 is an equidigital number, since it uses as much as digits as its factorization.

133520221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5805250.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 133520221 is about 11555.0950234085. The cubic root of 133520221 is about 511.1115331317. Note that the first 3 decimals are identical.

Adding to 133520221 its reverse (122025331), we get a palindrome (255545552).

The spelling of 133520221 in words is "one hundred thirty-three million, five hundred twenty thousand, two hundred twenty-one".