7881440 has 96 divisors (see below), whose sum is σ = 22063104. Its totient is φ = 2603520.

The previous prime is 7881373. The next prime is 7881487. The reversal of 7881440 is 441887.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 7881397 and 7881406.

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, 34607 + ... + 34833.

It is an arithmetic number, because the mean of its divisors is an integer number (229824).

Almost surely, 2^7881440 is an apocalyptic number.

7881440 is a gapful number since it is divisible by the number (70) 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 7881440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11031552).

7881440 is an abundant number, since it is smaller than the sum of its proper divisors (14181664).

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

7881440 is a wasteful number, since it uses less digits than its factorization.

7881440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280 (or 272 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 7881440 is about 2807.3902471869. The cubic root of 7881440 is about 199.0070786940.

It can be divided in two parts, 78 and 81440, that added together give a palindrome (81518).

The spelling of 7881440 in words is "seven million, eight hundred eighty-one thousand, four hundred forty".