8191268640 has 384 divisors, whose sum is σ = 29719872000. Its totient is φ = 2105671680.

The previous prime is 8191268623. The next prime is 8191268641. The reversal of 8191268640 is 468621918.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (8191268641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18243136 + ... + 18243584.

It is an arithmetic number, because the mean of its divisors is an integer number (77395500).

Almost surely, 2^8191268640 is an apocalyptic number.

8191268640 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 8191268640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14859936000).

8191268640 is an abundant number, since it is smaller than the sum of its proper divisors (21528603360).

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

8191268640 is a wasteful number, since it uses less digits than its factorization.

8191268640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 617 (or 603 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 45.

The square root of 8191268640 is about 90505.6276703278. The cubic root of 8191268640 is about 2015.8136874306.

The spelling of 8191268640 in words is "eight billion, one hundred ninety-one million, two hundred sixty-eight thousand, six hundred forty".