6443681 has 4 divisors (see below), whose sum is σ = 6450864. Its totient is φ = 6436500.

The previous prime is 6443677. The next prime is 6443719. The reversal of 6443681 is 1863446.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 6443681 - 2² = 6443677 is a prime.

It is a super-2 number, since 2×6443681² = 83042049659522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6443621) 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, 2015 + ... + 4116.

It is an arithmetic number, because the mean of its divisors is an integer number (1612716).

Almost surely, 2^6443681 is an apocalyptic number.

It is an amenable number.

6443681 is a deficient number, since it is larger than the sum of its proper divisors (7183).

6443681 is a wasteful number, since it uses less digits than its factorization.

6443681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7182.

The product of its digits is 13824, while the sum is 32.

The square root of 6443681 is about 2538.4406630843. The cubic root of 6443681 is about 186.0849902567.

It can be divided in two parts, 64 and 43681, that multiplied together give a square (2795584 = 1672²).

The spelling of 6443681 in words is "six million, four hundred forty-three thousand, six hundred eighty-one".