7971440 has 20 divisors (see below), whose sum is σ = 18533784. Its totient is φ = 3188544.

The previous prime is 7971413. The next prime is 7971443. The reversal of 7971440 is 441797.

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 7971397 and 7971406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7971443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49742 + ... + 49901.

Almost surely, 2^7971440 is an apocalyptic number.

It is an amenable number.

7971440 is an abundant number, since it is smaller than the sum of its proper divisors (10562344).

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

7971440 is a wasteful number, since it uses less digits than its factorization.

7971440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99656 (or 99650 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 7971440 is about 2823.3738682647. The cubic root of 7971440 is about 199.7617162169.

The spelling of 7971440 in words is "seven million, nine hundred seventy-one thousand, four hundred forty".