991262233728 has 1024 divisors, whose sum is σ = 3500679168000. Its totient is φ = 273336975360.

The previous prime is 991262233699. The next prime is 991262233729. The reversal of 991262233728 is 827332262199.

991262233728 is a `hidden beast` number, since 9 + 9 + 1 + 2 + 622 + 3 + 3 + 7 + 2 + 8 = 666.

It is a super-3 number, since 3×991262233728³ (a number of 37 digits) contains 333 as substring.

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 (991262233729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1243741426 + ... + 1243742222.

It is an arithmetic number, because the mean of its divisors is an integer number (3418632000).

Almost surely, 2^991262233728 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 991262233728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1750339584000).

991262233728 is an abundant number, since it is smaller than the sum of its proper divisors (2509416934272).

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

991262233728 is a wasteful number, since it uses less digits than its factorization.

991262233728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 930 (or 912 counting only the distinct ones).

The product of its digits is 3919104, while the sum is 54.

The spelling of 991262233728 in words is "nine hundred ninety-one billion, two hundred sixty-two million, two hundred thirty-three thousand, seven hundred twenty-eight".