7991893440 has 252 divisors, whose sum is σ = 28265740776. Its totient is φ = 2072549376.

The previous prime is 7991893417. The next prime is 7991893447. The reversal of 7991893440 is 443981997.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7991893447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3941707 + ... + 3943733.

It is an arithmetic number, because the mean of its divisors is an integer number (112165638).

Almost surely, 2^7991893440 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 7991893440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14132870388).

7991893440 is an abundant number, since it is smaller than the sum of its proper divisors (20273847336).

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

7991893440 is a wasteful number, since it uses less digits than its factorization.

7991893440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2124 (or 2074 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 54.

The square root of 7991893440 is about 89397.3905659444. The cubic root of 7991893440 is about 1999.3242250231.

The spelling of 7991893440 in words is "seven billion, nine hundred ninety-one million, eight hundred ninety-three thousand, four hundred forty".