231212131 has 4 divisors (see below), whose sum is σ = 231246232. Its totient is φ = 231178032.

The previous prime is 231212071. The next prime is 231212141. The reversal of 231212131 is 131212132.

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 231212131 - 2¹⁵ = 231179363 is a prime.

It is a super-2 number, since 2×231212131² = 106918099043122322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231212141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3045 + ... + 21718.

It is an arithmetic number, because the mean of its divisors is an integer number (57811558).

Almost surely, 2^231212131 is an apocalyptic number.

231212131 is a deficient number, since it is larger than the sum of its proper divisors (34101).

231212131 is an equidigital number, since it uses as much as digits as its factorization.

231212131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34100.

The product of its digits is 72, while the sum is 16.

The square root of 231212131 is about 15205.6611497166. The cubic root of 231212131 is about 613.7670063854.

Adding to 231212131 its reverse (131212132), we get a palindrome (362424263).

Subtracting from 231212131 its reverse (131212132), we obtain a palindrome (99999999).

It can be divided in two parts, 23121 and 2131, that added together give a palindrome (25252).

The spelling of 231212131 in words is "two hundred thirty-one million, two hundred twelve thousand, one hundred thirty-one".