991285305 has 8 divisors (see below), whose sum is σ = 1586056512. Its totient is φ = 528685488.

The previous prime is 991285289. The next prime is 991285307. The reversal of 991285305 is 503582199.

991285305 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 991285305 - 2⁴ = 991285289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (991285307) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33042829 + ... + 33042858.

It is an arithmetic number, because the mean of its divisors is an integer number (198257064).

Almost surely, 2^991285305 is an apocalyptic number.

It is an amenable number.

991285305 is a deficient number, since it is larger than the sum of its proper divisors (594771207).

991285305 is a wasteful number, since it uses less digits than its factorization.

991285305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66085695.

The product of its (nonzero) digits is 97200, while the sum is 42.

The square root of 991285305 is about 31484.6836572960. The cubic root of 991285305 is about 997.0866221388.

The spelling of 991285305 in words is "nine hundred ninety-one million, two hundred eighty-five thousand, three hundred five".