1321120243 has 2 divisors, whose sum is σ = 1321120244. Its totient is φ = 1321120242.

The previous prime is 1321120223. The next prime is 1321120343. The reversal of 1321120243 is 3420211231.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1321120243 - 2⁹ = 1321119731 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1321120243.

It is not a weakly prime, because it can be changed into another prime (1321120223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660560121 + 660560122.

It is an arithmetic number, because the mean of its divisors is an integer number (660560122).

Almost surely, 2^1321120243 is an apocalyptic number.

1321120243 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321120243 is an equidigital number, since it uses as much as digits as its factorization.

1321120243 is an evil number, because the sum of its binary digits is even.

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

The square root of 1321120243 is about 36347.2178164987. The cubic root of 1321120243 is about 1097.2715417392.

Adding to 1321120243 its reverse (3420211231), we get a palindrome (4741331474).

The spelling of 1321120243 in words is "one billion, three hundred twenty-one million, one hundred twenty thousand, two hundred forty-three".