991481760 has 144 divisors (see below), whose sum is σ = 3406876200. Its totient is φ = 262563840.

The previous prime is 991481713. The next prime is 991481789. The reversal of 991481760 is 67184199.

It is a happy number.

991481760 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 534719376 + 456762384 = 23124^2 + 21372^2 .

It is a tau number, because it is divible by the number of its divisors (144).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 212250 + ... + 216870.

Almost surely, 2^991481760 is an apocalyptic number.

991481760 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 991481760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1703438100).

991481760 is an abundant number, since it is smaller than the sum of its proper divisors (2415394440).

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

991481760 is a wasteful number, since it uses less digits than its factorization.

991481760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4791 (or 4780 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 991481760 is about 31487.8033530445. The cubic root of 991481760 is about 997.1524860270.

The spelling of 991481760 in words is "nine hundred ninety-one million, four hundred eighty-one thousand, seven hundred sixty".