991043648 has 112 divisors (see below), whose sum is σ = 2383048320. Its totient is φ = 399458304.

The previous prime is 991043639. The next prime is 991043659. The reversal of 991043648 is 846340199.

It is a tau number, because it is divible by the number of its divisors (112).

It is a super-2 number, since 2×991043648² = 1964335024482295808, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 991043599 and 991043608.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1472240 + ... + 1472912.

Almost surely, 2^991043648 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 991043648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1191524160).

991043648 is an abundant number, since it is smaller than the sum of its proper divisors (1392004672).

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

991043648 is a wasteful number, since it uses less digits than its factorization.

991043648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884 (or 874 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 991043648 is about 31480.8457319685. The cubic root of 991043648 is about 997.0055918026.

The spelling of 991043648 in words is "nine hundred ninety-one million, forty-three thousand, six hundred forty-eight".