991773328 has 240 divisors, whose sum is σ = 2577501696. Its totient is φ = 365783040.

The previous prime is 991773323. The next prime is 991773331. The reversal of 991773328 is 823377199.

It is a super-2 number, since 2×991773328² = 1967228668264391168, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (991773323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13585900 + ... + 13585972.

Almost surely, 2^991773328 is an apocalyptic number.

991773328 is a gapful number since it is divisible by the number (98) 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 991773328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1288750848).

991773328 is an abundant number, since it is smaller than the sum of its proper divisors (1585728368).

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

991773328 is a wasteful number, since it uses less digits than its factorization.

991773328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182 (or 169 counting only the distinct ones).

The product of its digits is 571536, while the sum is 49.

The square root of 991773328 is about 31492.4328688655. The cubic root of 991773328 is about 997.2502216496.

The spelling of 991773328 in words is "nine hundred ninety-one million, seven hundred seventy-three thousand, three hundred twenty-eight".