7921664 has 28 divisors (see below), whose sum is σ = 15858744. Its totient is φ = 3956736.

The previous prime is 7921631. The next prime is 7921679. The reversal of 7921664 is 4661297.

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7709 + ... + 8675.

Almost surely, 2^7921664 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 7921664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7929372).

7921664 is an abundant number, since it is smaller than the sum of its proper divisors (7937080).

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

7921664 is an frugal number, since it uses more digits than its factorization.

7921664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 993 (or 969 counting only the distinct ones).

The product of its digits is 18144, while the sum is 35.

The square root of 7921664 is about 2814.5450786939. The cubic root of 7921664 is about 199.3450575934.

The spelling of 7921664 in words is "seven million, nine hundred twenty-one thousand, six hundred sixty-four".