991430668800 has 1680 divisors, whose sum is σ = 4332511326528. Its totient is φ = 221560012800.

The previous prime is 991430668777. The next prime is 991430668801. The reversal of 991430668800 is 8866034199.

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 (991430668801) by changing a digit.

It is a polite number, since it can be written in 167 ways as a sum of consecutive naturals, for example, 1334361229 + ... + 1334361971.

Almost surely, 2^991430668800 is an apocalyptic number.

991430668800 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 991430668800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2166255663264).

991430668800 is an abundant number, since it is smaller than the sum of its proper divisors (3341080657728).

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

991430668800 is a wasteful number, since it uses less digits than its factorization.

991430668800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 813 (or 777 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 54.

The spelling of 991430668800 in words is "nine hundred ninety-one billion, four hundred thirty million, six hundred sixty-eight thousand, eight hundred".