231521133 has 8 divisors (see below), whose sum is σ = 313927200. Its totient is φ = 151731248.

The previous prime is 231521093. The next prime is 231521161. The reversal of 231521133 is 331125132.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 231521133 - 2⁹ = 231520621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231528133) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 653838 + ... + 654191.

It is an arithmetic number, because the mean of its divisors is an integer number (39240900).

Almost surely, 2^231521133 is an apocalyptic number.

It is an amenable number.

231521133 is a deficient number, since it is larger than the sum of its proper divisors (82406067).

231521133 is a wasteful number, since it uses less digits than its factorization.

231521133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1308091.

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

The square root of 231521133 is about 15215.8185123246. The cubic root of 231521133 is about 614.0403063582.

Adding to 231521133 its reverse (331125132), we get a palindrome (562646265).

The spelling of 231521133 in words is "two hundred thirty-one million, five hundred twenty-one thousand, one hundred thirty-three".