6421942871 has 4 divisors (see below), whose sum is σ = 6429385152. Its totient is φ = 6414500592.

The previous prime is 6421942843. The next prime is 6421942883. The reversal of 6421942871 is 1782491246.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6421942871 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 (6421942771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3719846 + ... + 3721571.

It is an arithmetic number, because the mean of its divisors is an integer number (1607346288).

Almost surely, 2^6421942871 is an apocalyptic number.

6421942871 is a deficient number, since it is larger than the sum of its proper divisors (7442281).

6421942871 is an equidigital number, since it uses as much as digits as its factorization.

6421942871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7442280.

The product of its digits is 193536, while the sum is 44.

The square root of 6421942871 is about 80137.0255936668. The cubic root of 6421942871 is about 1858.7549835783.

The spelling of 6421942871 in words is "six billion, four hundred twenty-one million, nine hundred forty-two thousand, eight hundred seventy-one".