6721816 has 16 divisors (see below), whose sum is σ = 12652200. Its totient is φ = 3347904.

The previous prime is 6721789. The next prime is 6721843. The reversal of 6721816 is 6181276.

6721816 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (6721789) and next prime (6721843).

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, 780 + ... + 3748.

Almost surely, 2^6721816 is an apocalyptic number.

It is an amenable number.

6721816 is a deficient number, since it is larger than the sum of its proper divisors (5930384).

6721816 is a wasteful number, since it uses less digits than its factorization.

6721816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3258 (or 3254 counting only the distinct ones).

The product of its digits is 4032, while the sum is 31.

The square root of 6721816 is about 2592.6465243068. The cubic root of 6721816 is about 188.7247563568.

The spelling of 6721816 in words is "six million, seven hundred twenty-one thousand, eight hundred sixteen".