991856160 has 288 divisors, whose sum is σ = 3702246912. Its totient is φ = 240721920.

The previous prime is 991856153. The next prime is 991856167. The reversal of 991856160 is 61658199.

It is an interprime number because it is at equal distance from previous prime (991856153) and next prime (991856167).

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (991856167) 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, 758227 + ... + 759533.

It is an arithmetic number, because the mean of its divisors is an integer number (12855024).

Almost surely, 2^991856160 is an apocalyptic number.

991856160 is a gapful number since it is divisible by the number (90) 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 991856160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1851123456).

991856160 is an abundant number, since it is smaller than the sum of its proper divisors (2710390752).

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

991856160 is a wasteful number, since it uses less digits than its factorization.

991856160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1376 (or 1365 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The square root of 991856160 is about 31493.7479509823. The cubic root of 991856160 is about 997.2779840185.

It can be divided in two parts, 991856 and 160, that added together give a square (992016 = 996²).

The spelling of 991856160 in words is "nine hundred ninety-one million, eight hundred fifty-six thousand, one hundred sixty".