1643345321 has 8 divisors (see below), whose sum is σ = 1732540320. Its totient is φ = 1554420672.

The previous prime is 1643345311. The next prime is 1643345323. The reversal of 1643345321 is 1235433461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1643345321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1643345323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55040 + ... + 79473.

It is an arithmetic number, because the mean of its divisors is an integer number (216567540).

Almost surely, 2^1643345321 is an apocalyptic number.

It is an amenable number.

1643345321 is a deficient number, since it is larger than the sum of its proper divisors (89194999).

1643345321 is a wasteful number, since it uses less digits than its factorization.

1643345321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135175.

The product of its digits is 25920, while the sum is 32.

The square root of 1643345321 is about 40538.1958281323. The cubic root of 1643345321 is about 1180.0750026539.

Adding to 1643345321 its reverse (1235433461), we get a palindrome (2878778782).

The spelling of 1643345321 in words is "one billion, six hundred forty-three million, three hundred forty-five thousand, three hundred twenty-one".