7904640 has 128 divisors (see below), whose sum is σ = 26438400. Its totient is φ = 2004992.

The previous prime is 7904639. The next prime is 7904651. The reversal of 7904640 is 464097.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 7904598 and 7904607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44071 + ... + 44249.

It is an arithmetic number, because the mean of its divisors is an integer number (206550).

Almost surely, 2^7904640 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 7904640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13219200).

7904640 is an abundant number, since it is smaller than the sum of its proper divisors (18533760).

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

7904640 is a wasteful number, since it uses less digits than its factorization.

7904640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224 (or 212 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 7904640 is about 2811.5191623035. The cubic root of 7904640 is about 199.2021547806.

The spelling of 7904640 in words is "seven million, nine hundred four thousand, six hundred forty".