231520133 has 4 divisors (see below), whose sum is σ = 249329388. Its totient is φ = 213710880.

The previous prime is 231520129. The next prime is 231520171. The reversal of 231520133 is 331025132.

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 158810404 + 72709729 = 12602^2 + 8527^2 .

It is a cyclic number.

It is not a de Polignac number, because 231520133 - 2² = 231520129 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 (231528133) 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, 8904608 + ... + 8904633.

It is an arithmetic number, because the mean of its divisors is an integer number (62332347).

Almost surely, 2^231520133 is an apocalyptic number.

It is an amenable number.

231520133 is a deficient number, since it is larger than the sum of its proper divisors (17809255).

231520133 is a wasteful number, since it uses less digits than its factorization.

231520133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17809254.

The product of its (nonzero) digits is 540, while the sum is 20.

The square root of 231520133 is about 15215.7856517500. The cubic root of 231520133 is about 614.0394222903.

Adding to 231520133 its reverse (331025132), we get a palindrome (562545265).

The spelling of 231520133 in words is "two hundred thirty-one million, five hundred twenty thousand, one hundred thirty-three".