991229944320 has 800 divisors, whose sum is σ = 4426385014656. Its totient is φ = 205966540800.

The previous prime is 991229944319. The next prime is 991229944321. The reversal of 991229944320 is 23449922199.

991229944320 is a `hidden beast` number, since 9 + 9 + 1 + 229 + 94 + 4 + 320 = 666.

It is an interprime number because it is at equal distance from previous prime (991229944319) and next prime (991229944321).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (991229944321) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 15935680 + ... + 15997760.

Almost surely, 2^991229944320 is an apocalyptic number.

991229944320 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 991229944320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2213192507328).

991229944320 is an abundant number, since it is smaller than the sum of its proper divisors (3435155070336).

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

991229944320 is a wasteful number, since it uses less digits than its factorization.

991229944320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62134 (or 62109 counting only the distinct ones).

The product of its (nonzero) digits is 2519424, while the sum is 54.

The spelling of 991229944320 in words is "nine hundred ninety-one billion, two hundred twenty-nine million, nine hundred forty-four thousand, three hundred twenty".