1231433531 has 4 divisors (see below), whose sum is σ = 1236811200. Its totient is φ = 1226055864.

The previous prime is 1231433521. The next prime is 1231433537. The reversal of 1231433531 is 1353341321.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1231433531 - 2¹⁰ = 1231432507 is a prime.

It is a super-2 number, since 2×1231433531² = 3032857082542255922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1231433531.

It is not an unprimeable number, because it can be changed into a prime (1231433537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2688491 + ... + 2688948.

It is an arithmetic number, because the mean of its divisors is an integer number (309202800).

Almost surely, 2^1231433531 is an apocalyptic number.

1231433531 is a deficient number, since it is larger than the sum of its proper divisors (5377669).

1231433531 is an equidigital number, since it uses as much as digits as its factorization.

1231433531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5377668.

The product of its digits is 3240, while the sum is 26.

The square root of 1231433531 is about 35091.7872300628. The cubic root of 1231433531 is about 1071.8573531489.

Adding to 1231433531 its reverse (1353341321), we get a palindrome (2584774852).

The spelling of 1231433531 in words is "one billion, two hundred thirty-one million, four hundred thirty-three thousand, five hundred thirty-one".