6421705 has 4 divisors (see below), whose sum is σ = 7706052. Its totient is φ = 5137360.

The previous prime is 6421703. The next prime is 6421721. The reversal of 6421705 is 5071246.

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

It can be written as a sum of positive squares in 2 ways, for example, as 927369 + 5494336 = 963^2 + 2344^2 .

It is not a de Polignac number, because 6421705 - 2¹ = 6421703 is a prime.

It is a Duffinian number.

6421705 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 6421705.

It is not an unprimeable number, because it can be changed into a prime (6421703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 642166 + ... + 642175.

It is an arithmetic number, because the mean of its divisors is an integer number (1926513).

Almost surely, 2^6421705 is an apocalyptic number.

It is an amenable number.

6421705 is a deficient number, since it is larger than the sum of its proper divisors (1284347).

6421705 is a wasteful number, since it uses less digits than its factorization.

6421705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1284346.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 6421705 is about 2534.1083244408. The cubic root of 6421705 is about 185.8732033651.

The spelling of 6421705 in words is "six million, four hundred twenty-one thousand, seven hundred five".