7928640 has 84 divisors (see below), whose sum is σ = 27281124. Its totient is φ = 2113536.

The previous prime is 7928623. The next prime is 7928651. The reversal of 7928640 is 468297.

7928640 is a `hidden beast` number, since 7 + 9 + 2 + 8 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 5419584 + 2509056 = 2328^2 + 1584^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 7928595 and 7928604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1504 + ... + 4256.

Almost surely, 2^7928640 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 7928640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13640562).

7928640 is an abundant number, since it is smaller than the sum of its proper divisors (19352484).

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

7928640 is a wasteful number, since it uses less digits than its factorization.

7928640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2776 (or 2763 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 7928640 is about 2815.7840826313. The cubic root of 7928640 is about 199.4035563765.

The spelling of 7928640 in words is "seven million, nine hundred twenty-eight thousand, six hundred forty".