6421689 has 12 divisors (see below), whose sum is σ = 9326356. Its totient is φ = 4257792.

The previous prime is 6421643. The next prime is 6421697. The reversal of 6421689 is 9861246.

6421689 is a `hidden beast` number, since 642 + 1 + 6 + 8 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1016064 + 5405625 = 1008^2 + 2325^2 .

It is not a de Polignac number, because 6421689 - 2⁷ = 6421561 is a prime.

It is a super-2 number, since 2×6421689² = 82476179225442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6421589) 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, 112 + ... + 3585.

Almost surely, 2^6421689 is an apocalyptic number.

It is an amenable number.

6421689 is a deficient number, since it is larger than the sum of its proper divisors (2904667).

6421689 is a wasteful number, since it uses less digits than its factorization.

6421689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3896 (or 3893 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 6421689 is about 2534.1051675098. The cubic root of 6421689 is about 185.8730489942.

The spelling of 6421689 in words is "six million, four hundred twenty-one thousand, six hundred eighty-nine".