991606000440 has 256 divisors, whose sum is σ = 3364410816000. Its totient is φ = 231598868480.

The previous prime is 991606000439. The next prime is 991606000543. The reversal of 991606000440 is 44000606199.

It is a super-2 number, since 2×991606000440² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 17849026 + ... + 17904494.

It is an arithmetic number, because the mean of its divisors is an integer number (13142229750).

Almost surely, 2^991606000440 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 991606000440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1682205408000).

991606000440 is an abundant number, since it is smaller than the sum of its proper divisors (2372804815560).

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

991606000440 is a wasteful number, since it uses less digits than its factorization.

991606000440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55990 (or 55986 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 39.

The spelling of 991606000440 in words is "nine hundred ninety-one billion, six hundred six million, four hundred forty", and thus it is an aban number.