133513221 has 4 divisors (see below), whose sum is σ = 178017632. Its totient is φ = 89008812.

The previous prime is 133513217. The next prime is 133513241. The reversal of 133513221 is 122315331.

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.

It is not a de Polignac number, because 133513221 - 2² = 133513217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133513241) 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, 22252201 + ... + 22252206.

It is an arithmetic number, because the mean of its divisors is an integer number (44504408).

Almost surely, 2^133513221 is an apocalyptic number.

It is an amenable number.

133513221 is a deficient number, since it is larger than the sum of its proper divisors (44504411).

133513221 is an equidigital number, since it uses as much as digits as its factorization.

133513221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44504410.

The product of its digits is 540, while the sum is 21.

The square root of 133513221 is about 11554.7921227515. The cubic root of 133513221 is about 511.1026010433.

Adding to 133513221 its reverse (122315331), we get a palindrome (255828552).

The spelling of 133513221 in words is "one hundred thirty-three million, five hundred thirteen thousand, two hundred twenty-one".