6543021021 has 4 divisors (see below), whose sum is σ = 8724028032. Its totient is φ = 4362014012.

The previous prime is 6543021007. The next prime is 6543021053. The reversal of 6543021021 is 1201203456.

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 a cyclic number.

It is not a de Polignac number, because 6543021021 - 2⁵ = 6543020989 is a prime.

It is a super-2 number, since 2×6543021021² = 85622248162495764882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 6543020982 and 6543021000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6543021521) 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, 1090503501 + ... + 1090503506.

It is an arithmetic number, because the mean of its divisors is an integer number (2181007008).

Almost surely, 2^6543021021 is an apocalyptic number.

It is an amenable number.

6543021021 is a deficient number, since it is larger than the sum of its proper divisors (2181007011).

6543021021 is a wasteful number, since it uses less digits than its factorization.

6543021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2181007010.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 6543021021 is about 80888.9425137948. The cubic root of 6543021021 is about 1870.3638725890.

Adding to 6543021021 its reverse (1201203456), we get a palindrome (7744224477).

The spelling of 6543021021 in words is "six billion, five hundred forty-three million, twenty-one thousand, twenty-one".