1240205243 has 4 divisors (see below), whose sum is σ = 1240645848. Its totient is φ = 1239764640.

The previous prime is 1240205207. The next prime is 1240205261. The reversal of 1240205243 is 3425020421.

It is a happy number.

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 1240205243 - 2¹⁰ = 1240204219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1240205273) 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, 216053 + ... + 221718.

It is an arithmetic number, because the mean of its divisors is an integer number (310161462).

Almost surely, 2^1240205243 is an apocalyptic number.

1240205243 is a deficient number, since it is larger than the sum of its proper divisors (440605).

1240205243 is an equidigital number, since it uses as much as digits as its factorization.

1240205243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 440604.

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 1240205243 is about 35216.5478575059. The cubic root of 1240205243 is about 1074.3963419564.

Adding to 1240205243 its reverse (3425020421), we get a palindrome (4665225664).

The spelling of 1240205243 in words is "one billion, two hundred forty million, two hundred five thousand, two hundred forty-three".