6921216 has 66 divisors (see below), whose sum is σ = 20011472. Its totient is φ = 2304000.

The previous prime is 6921209. The next prime is 6921221. The reversal of 6921216 is 6121296.

It is a nude number because it is divisible by every one of its digits.

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

It is a self number, because there is not a number n which added to its sum of digits gives 6921216.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8841 + ... + 9591.

Almost surely, 2^6921216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6921216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10005736).

6921216 is an abundant number, since it is smaller than the sum of its proper divisors (13090256).

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

6921216 is a wasteful number, since it uses less digits than its factorization.

6921216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 777 (or 756 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 6921216 is about 2630.8204043606. The cubic root of 6921216 is about 190.5727500262.

The spelling of 6921216 in words is "six million, nine hundred twenty-one thousand, two hundred sixteen".