991424985 has 32 divisors (see below), whose sum is σ = 1625868288. Its totient is φ = 515605440.

The previous prime is 991424971. The next prime is 991424999. The reversal of 991424985 is 589424199.

It is an interprime number because it is at equal distance from previous prime (991424971) and next prime (991424999).

It is not a de Polignac number, because 991424985 - 2¹⁵ = 991392217 is a prime.

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 31 ways as a sum of consecutive naturals, for example, 625504 + ... + 627086.

It is an arithmetic number, because the mean of its divisors is an integer number (50808384).

Almost surely, 2^991424985 is an apocalyptic number.

It is an amenable number.

991424985 is a deficient number, since it is larger than the sum of its proper divisors (634443303).

991424985 is a wasteful number, since it uses less digits than its factorization.

991424985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2605.

The product of its digits is 933120, while the sum is 51.

The square root of 991424985 is about 31486.9018005900. The cubic root of 991424985 is about 997.1334524232.

The spelling of 991424985 in words is "nine hundred ninety-one million, four hundred twenty-four thousand, nine hundred eighty-five".