6445123321 has 16 divisors (see below), whose sum is σ = 8094352000. Its totient is φ = 5099434704.

The previous prime is 6445123303. The next prime is 6445123343. The reversal of 6445123321 is 1233215446.

It is not a de Polignac number, because 6445123321 - 2⁹ = 6445122809 is a prime.

It is a super-2 number, since 2×6445123321² = 83079229245796138082, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6445123621) 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, 718251 + ... + 727168.

It is an arithmetic number, because the mean of its divisors is an integer number (505897000).

Almost surely, 2^6445123321 is an apocalyptic number.

It is an amenable number.

6445123321 is a deficient number, since it is larger than the sum of its proper divisors (1649228679).

6445123321 is a wasteful number, since it uses less digits than its factorization.

6445123321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1445453 (or 1445439 counting only the distinct ones).

The product of its digits is 17280, while the sum is 31.

The square root of 6445123321 is about 80281.5254027974. The cubic root of 6445123321 is about 1860.9887332892.

Adding to 6445123321 its reverse (1233215446), we get a palindrome (7678338767).

The spelling of 6445123321 in words is "six billion, four hundred forty-five million, one hundred twenty-three thousand, three hundred twenty-one".