9991313640 has 864 divisors, whose sum is σ = 43142561280. Its totient is φ = 1995840000.

The previous prime is 9991313623. The next prime is 9991313663. The reversal of 9991313640 is 463131999.

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

It is an unprimeable number.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 66167565 + ... + 66167715.

It is an arithmetic number, because the mean of its divisors is an integer number (49933520).

Almost surely, 2^9991313640 is an apocalyptic number.

9991313640 is a gapful number since it is divisible by the number (90) 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 9991313640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21571280640).

9991313640 is an abundant number, since it is smaller than the sum of its proper divisors (33151247640).

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

9991313640 is a wasteful number, since it uses less digits than its factorization.

9991313640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235 (or 210 counting only the distinct ones).

The product of its (nonzero) digits is 157464, while the sum is 45.

The square root of 9991313640 is about 99956.5587642952. The cubic root of 9991313640 is about 2153.8107028139.

The spelling of 9991313640 in words is "nine billion, nine hundred ninety-one million, three hundred thirteen thousand, six hundred forty".