991047 has 16 divisors (see below), whose sum is σ = 1410048.
Its totient is φ = 617760.
The previous prime is 991043. The next prime is 991057. The reversal of 991047 is 740199.
It is not a de Polignac number, because 991047 - 22 = 991043 is a prime.
It is a plaindrome in base 15.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991047.
It is not an unprimeable number, because it can be changed into a prime (991043) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3522 + ... + 3792.
It is an arithmetic number, because the mean of its divisors is an integer number (88128).
2991047 is an apocalyptic number.
991047 is the 813-rd pentagonal number.
991047 is a deficient number, since it is larger than the sum of its proper divisors (419001).
991047 is a wasteful number, since it uses less digits than its factorization.
991047 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 350.
The product of its (nonzero) digits is 2268, while the sum is 30.
The square root of 991047 is about 995.5134353689.
The cubic root of 991047 is about 99.7006715856.
The spelling of 991047 in words is "nine hundred ninety-one thousand, forty-seven".