991424 has 28 divisors (see below), whose sum is σ = 2249424. Its totient is φ = 424704.

The previous prime is 991409. The next prime is 991427. The reversal of 991424 is 424199.

It is a tau number, because it is divible by the number of its divisors (28).

It is not an unprimeable number, because it can be changed into a prime (991427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 659 + ... + 1554.

2⁹⁹¹⁴²⁴ is an apocalyptic number.

It is an amenable number.

991424 is an abundant number, since it is smaller than the sum of its proper divisors (1258000).

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

991424 is a wasteful number, since it uses less digits than its factorization.

991424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2232 (or 2222 counting only the distinct ones).

The product of its digits is 2592, while the sum is 29.

The square root of 991424 is about 995.7027668938. The cubic root of 991424 is about 99.7133122199.

The spelling of 991424 in words is "nine hundred ninety-one thousand, four hundred twenty-four".