991493429760 has 640 divisors, whose sum is σ = 3575085465600. Its totient is φ = 260437524480.

The previous prime is 991493429749. The next prime is 991493429791. The reversal of 991493429760 is 67924394199.

991493429760 is a `hidden beast` number, since 9 + 9 + 149 + 3 + 429 + 7 + 60 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1571304645 + ... + 1571305275.

It is an arithmetic number, because the mean of its divisors is an integer number (5586071040).

Almost surely, 2^991493429760 is an apocalyptic number.

991493429760 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 991493429760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1787542732800).

991493429760 is an abundant number, since it is smaller than the sum of its proper divisors (2583592035840).

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

991493429760 is a wasteful number, since it uses less digits than its factorization.

991493429760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 969 (or 947 counting only the distinct ones).

The product of its (nonzero) digits is 26453952, while the sum is 63.

The spelling of 991493429760 in words is "nine hundred ninety-one billion, four hundred ninety-three million, four hundred twenty-nine thousand, seven hundred sixty".