1243320121 has 16 divisors (see below), whose sum is σ = 1306368000. Its totient is φ = 1182227200.

The previous prime is 1243320079. The next prime is 1243320151. The reversal of 1243320121 is 1210233421.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1243320121 - 2²³ = 1234931513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1243320151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 256680 + ... + 261478.

It is an arithmetic number, because the mean of its divisors is an integer number (81648000).

Almost surely, 2^1243320121 is an apocalyptic number.

It is an amenable number.

1243320121 is a deficient number, since it is larger than the sum of its proper divisors (63047879).

1243320121 is an equidigital number, since it uses as much as digits as its factorization.

1243320121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5000.

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

The square root of 1243320121 is about 35260.7447595765. The cubic root of 1243320121 is about 1075.2950683796.

Adding to 1243320121 its reverse (1210233421), we get a palindrome (2453553542).

The spelling of 1243320121 in words is "one billion, two hundred forty-three million, three hundred twenty thousand, one hundred twenty-one".