6555221021 has 8 divisors (see below), whose sum is σ = 6570797760. Its totient is φ = 6539664352.

The previous prime is 6555221009. The next prime is 6555221051. The reversal of 6555221021 is 1201225556.

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-6555221021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6555221051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 791126 + ... + 799368.

It is an arithmetic number, because the mean of its divisors is an integer number (821349720).

Almost surely, 2^6555221021 is an apocalyptic number.

It is an amenable number.

6555221021 is a deficient number, since it is larger than the sum of its proper divisors (15576739).

6555221021 is an equidigital number, since it uses as much as digits as its factorization.

6555221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10035.

The product of its (nonzero) digits is 6000, while the sum is 29.

The square root of 6555221021 is about 80964.3194314631. The cubic root of 6555221021 is about 1871.5256331662.

Adding to 6555221021 its reverse (1201225556), we get a palindrome (7756446577).

The spelling of 6555221021 in words is "six billion, five hundred fifty-five million, two hundred twenty-one thousand, twenty-one".