8391040 has 64 divisors (see below), whose sum is σ = 22937760. Its totient is φ = 2875392.

The previous prime is 8391037. The next prime is 8391073. The reversal of 8391040 is 401938.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 8390996 and 8391014.

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, 3544 + ... + 5416.

Almost surely, 2^8391040 is an apocalyptic number.

8391040 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 8391040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11468880).

8391040 is an abundant number, since it is smaller than the sum of its proper divisors (14546720).

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

8391040 is a wasteful number, since it uses less digits than its factorization.

8391040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1899 (or 1887 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 8391040 is about 2896.7291899658. The cubic root of 8391040 is about 203.2069685750.

Adding to 8391040 its reverse (401938), we get a palindrome (8792978).

The spelling of 8391040 in words is "eight million, three hundred ninety-one thousand, forty".