1243320321 has 4 divisors (see below), whose sum is σ = 1657760432. Its totient is φ = 828880212.

The previous prime is 1243320319. The next prime is 1243320343. The reversal of 1243320321 is 1230233421.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1243320321 - 2¹ = 1243320319 is a prime.

It is a super-2 number, since 2×1243320321² = 3091690841223086082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1243320301) 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, 207220051 + ... + 207220056.

It is an arithmetic number, because the mean of its divisors is an integer number (414440108).

Almost surely, 2^1243320321 is an apocalyptic number.

It is an amenable number.

1243320321 is a deficient number, since it is larger than the sum of its proper divisors (414440111).

1243320321 is an equidigital number, since it uses as much as digits as its factorization.

1243320321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414440110.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 1243320321 is about 35260.7475955913. The cubic root of 1243320321 is about 1075.2951260368.

Adding to 1243320321 its reverse (1230233421), we get a palindrome (2473553742).

The spelling of 1243320321 in words is "one billion, two hundred forty-three million, three hundred twenty thousand, three hundred twenty-one".