6445681 has 16 divisors (see below), whose sum is σ = 7459200. Its totient is φ = 5512320.

The previous prime is 6445661. The next prime is 6445711. The reversal of 6445681 is 1865446.

It is not a de Polignac number, because 6445681 - 2⁹ = 6445169 is a prime.

It is a super-2 number, since 2×6445681² = 83093607107522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6445661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18295 + ... + 18643.

It is an arithmetic number, because the mean of its divisors is an integer number (466200).

Almost surely, 2^6445681 is an apocalyptic number.

6445681 is the 1606-th heptagonal number.

It is an amenable number.

6445681 is a deficient number, since it is larger than the sum of its proper divisors (1013519).

6445681 is a wasteful number, since it uses less digits than its factorization.

6445681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456.

The product of its digits is 23040, while the sum is 34.

The square root of 6445681 is about 2538.8345751545. The cubic root of 6445681 is about 186.1042407173.

The spelling of 6445681 in words is "six million, four hundred forty-five thousand, six hundred eighty-one".