991042 has 16 divisors (see below), whose sum is σ = 1636992. Its totient is φ = 447120.

The previous prime is 991037. The next prime is 991043. The reversal of 991042 is 240199.

It is a junction number, because it is equal to n+sod(n) for n = 990998 and 991016.

It is not an unprimeable number, because it can be changed into a prime (991043) by changing a digit.

991042 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 817 + ... + 1627.

It is an arithmetic number, because the mean of its divisors is an integer number (102312).

2⁹⁹¹⁰⁴² is an apocalyptic number.

991042 is a deficient number, since it is larger than the sum of its proper divisors (645950).

991042 is a wasteful number, since it uses less digits than its factorization.

991042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 873.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 991042 is about 995.5109240988. The cubic root of 991042 is about 99.7005039164.

The spelling of 991042 in words is "nine hundred ninety-one thousand, forty-two".