991745164800 has 960 divisors, whose sum is σ = 3958756623360. Its totient is φ = 241723146240.

The previous prime is 991745164789. The next prime is 991745164937. The reversal of 991745164800 is 8461547199.

991745164800 is a `hidden beast` number, since 9 + 91 + 74 + 5 + 1 + 6 + 480 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

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

It is a congruent number.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 480728569 + ... + 480730631.

It is an arithmetic number, because the mean of its divisors is an integer number (4123704816).

Almost surely, 2^991745164800 is an apocalyptic number.

991745164800 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 991745164800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1979378311680).

991745164800 is an abundant number, since it is smaller than the sum of its proper divisors (2967011458560).

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

991745164800 is a wasteful number, since it uses less digits than its factorization.

991745164800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2220 (or 2193 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 991745164800 in words is "nine hundred ninety-one billion, seven hundred forty-five million, one hundred sixty-four thousand, eight hundred".