6721656 has 16 divisors (see below), whose sum is σ = 16804200. Its totient is φ = 2240544.

The previous prime is 6721609. The next prime is 6721661. The reversal of 6721656 is 6561276.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140011 + ... + 140058.

Almost surely, 2^6721656 is an apocalyptic number.

It is an amenable number.

6721656 is an abundant number, since it is smaller than the sum of its proper divisors (10082544).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6721656 is a wasteful number, since it uses less digits than its factorization.

6721656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280078 (or 280074 counting only the distinct ones).

The product of its digits is 15120, while the sum is 33.

The square root of 6721656 is about 2592.6156676222. The cubic root of 6721656 is about 188.7232589340.

The spelling of 6721656 in words is "six million, seven hundred twenty-one thousand, six hundred fifty-six".