231221143 has 4 divisors (see below), whose sum is σ = 231258928. Its totient is φ = 231183360.

The previous prime is 231221129. The next prime is 231221167. The reversal of 231221143 is 341122132.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231221143 is a prime.

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 231221143.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231221113) 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, 7371 + ... + 22732.

It is an arithmetic number, because the mean of its divisors is an integer number (57814732).

Almost surely, 2^231221143 is an apocalyptic number.

231221143 is a deficient number, since it is larger than the sum of its proper divisors (37785).

231221143 is an equidigital number, since it uses as much as digits as its factorization.

231221143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37784.

The product of its digits is 288, while the sum is 19.

The square root of 231221143 is about 15205.9574838285. The cubic root of 231221143 is about 613.7749805869.

Adding to 231221143 its reverse (341122132), we get a palindrome (572343275).

The spelling of 231221143 in words is "two hundred thirty-one million, two hundred twenty-one thousand, one hundred forty-three".