231505133 has 4 divisors (see below), whose sum is σ = 245123100. Its totient is φ = 217887168.

The previous prime is 231505123. The next prime is 231505159. The reversal of 231505133 is 331505132.

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 216590089 + 14915044 = 14717^2 + 3862^2 .

It is a cyclic number.

It is not a de Polignac number, because 231505133 - 2⁸ = 231504877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 231505099 and 231505108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231505103) 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, 6808958 + ... + 6808991.

It is an arithmetic number, because the mean of its divisors is an integer number (61280775).

Almost surely, 2^231505133 is an apocalyptic number.

It is an amenable number.

231505133 is a deficient number, since it is larger than the sum of its proper divisors (13617967).

231505133 is a wasteful number, since it uses less digits than its factorization.

231505133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13617966.

The product of its (nonzero) digits is 1350, while the sum is 23.

The square root of 231505133 is about 15215.2927346141. The cubic root of 231505133 is about 614.0261609666.

Subtracting 231505133 from its reverse (331505132), we obtain a palindrome (99999999).

The spelling of 231505133 in words is "two hundred thirty-one million, five hundred five thousand, one hundred thirty-three".