6681649 has 8 divisors (see below), whose sum is σ = 7234920. Its totient is φ = 6134016.

The previous prime is 6681637. The next prime is 6681671. The reversal of 6681649 is 9461866.

It can be written as a sum of positive squares in 4 ways, for example, as 1587600 + 5094049 = 1260^2 + 2257^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6681649 - 2⁹ = 6681137 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 (6681679) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1257 + ... + 3865.

It is an arithmetic number, because the mean of its divisors is an integer number (904365).

Almost surely, 2^6681649 is an apocalyptic number.

It is an amenable number.

6681649 is a deficient number, since it is larger than the sum of its proper divisors (553271).

6681649 is a wasteful number, since it uses less digits than its factorization.

6681649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2819.

The product of its digits is 62208, while the sum is 40.

The square root of 6681649 is about 2584.8885856067. Note that the first 3 decimals coincide. The cubic root of 6681649 is about 188.3480894452.

The spelling of 6681649 in words is "six million, six hundred eighty-one thousand, six hundred forty-nine".