7881664 has 56 divisors (see below), whose sum is σ = 18194528. Its totient is φ = 3317760.

The previous prime is 7881647. The next prime is 7881689. The reversal of 7881664 is 4661887.

It is a tau number, because it is divible by the number of its divisors (56).

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32584 + ... + 32824.

Almost surely, 2^7881664 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 7881664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9097264).

7881664 is an abundant number, since it is smaller than the sum of its proper divisors (10312864).

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

7881664 is a wasteful number, since it uses less digits than its factorization.

7881664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333 (or 323 counting only the distinct ones).

The product of its digits is 64512, while the sum is 40.

The square root of 7881664 is about 2807.4301416064. The cubic root of 7881664 is about 199.0089640163.

The spelling of 7881664 in words is "seven million, eight hundred eighty-one thousand, six hundred sixty-four".