991087064 has 64 divisors (see below), whose sum is σ = 2122848000.
Its totient is φ = 429627520.
The previous prime is 991087061. The next prime is 991087067. The reversal of 991087064 is 460780199.
991087064 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is an interprime number because it is at equal distance from previous prime (991087061) and next prime (991087067).
Together with 1131760935 it forms a betrothed pair.
It is a Harshad number since it is a multiple of its sum of digits (44).
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (991087061) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 209477 + ... + 214155.
It is an arithmetic number, because the mean of its divisors is an integer number (33169500).
Almost surely, 2991087064 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 991087064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1061424000).
991087064 is an abundant number, since it is smaller than the sum of its proper divisors (1131760936).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
991087064 is a wasteful number, since it uses less digits than its factorization.
991087064 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 4808 (or 4804 counting only the distinct ones).
The product of its (nonzero) digits is 108864, while the sum is 44.
The square root of 991087064 is about 31481.5352865771.
The cubic root of 991087064 is about 997.0201506511.
The spelling of 991087064 in words is "nine hundred ninety-one million, eighty-seven thousand, sixty-four".