991626983424 has 1152 divisors, whose sum is σ = 3777065510400. Its totient is φ = 254910136320.

The previous prime is 991626983393. The next prime is 991626983447. The reversal of 991626983424 is 424389626199.

991626983424 is a `hidden beast` number, since 9 + 91 + 62 + 69 + 8 + 3 + 424 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

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, 10222958544 + ... + 10222958640.

It is an arithmetic number, because the mean of its divisors is an integer number (3278702700).

Almost surely, 2^991626983424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991626983424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1888532755200).

991626983424 is an abundant number, since it is smaller than the sum of its proper divisors (2785438526976).

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

991626983424 is an frugal number, since it uses more digits than its factorization.

991626983424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174 (or 120 counting only the distinct ones).

The product of its digits is 40310784, while the sum is 63.

The spelling of 991626983424 in words is "nine hundred ninety-one billion, six hundred twenty-six million, nine hundred eighty-three thousand, four hundred twenty-four".