133231521 has 16 divisors (see below), whose sum is σ = 184209408. Its totient is φ = 85563600.

The previous prime is 133231493. The next prime is 133231523. The reversal of 133231521 is 125132331.

It is not a de Polignac number, because 133231521 - 2⁶ = 133231457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (133231523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17956 + ... + 24266.

It is an arithmetic number, because the mean of its divisors is an integer number (11513088).

Almost surely, 2^133231521 is an apocalyptic number.

It is an amenable number.

133231521 is a deficient number, since it is larger than the sum of its proper divisors (50977887).

133231521 is a wasteful number, since it uses less digits than its factorization.

133231521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6572.

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

The square root of 133231521 is about 11542.5959385227. The cubic root of 133231521 is about 510.7428888987.

Adding to 133231521 its reverse (125132331), we get a palindrome (258363852).

The spelling of 133231521 in words is "one hundred thirty-three million, two hundred thirty-one thousand, five hundred twenty-one".