6556663421 has 12 divisors (see below), whose sum is σ = 8236470816. Its totient is φ = 5109087720.

The previous prime is 6556663367. The next prime is 6556663423. The reversal of 6556663421 is 1243666556.

It is not a de Polignac number, because 6556663421 - 2¹⁰ = 6556662397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6556663423) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3869675 + ... + 3871368.

It is an arithmetic number, because the mean of its divisors is an integer number (686372568).

Almost surely, 2^6556663421 is an apocalyptic number.

It is an amenable number.

6556663421 is a deficient number, since it is larger than the sum of its proper divisors (1679807395).

6556663421 is a wasteful number, since it uses less digits than its factorization.

6556663421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7741072 (or 7741061 counting only the distinct ones).

The product of its digits is 777600, while the sum is 44.

The square root of 6556663421 is about 80973.2265690333. The cubic root of 6556663421 is about 1871.6628922351.

The spelling of 6556663421 in words is "six billion, five hundred fifty-six million, six hundred sixty-three thousand, four hundred twenty-one".