991673 has 4 divisors (see below), whose sum is σ = 994548. Its totient is φ = 988800.

The previous prime is 991663. The next prime is 991693. The reversal of 991673 is 376199.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 896809 + 94864 = 947^2 + 308^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991673 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991673.

It is not an unprimeable number, because it can be changed into a prime (991603) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 836 + ... + 1637.

It is an arithmetic number, because the mean of its divisors is an integer number (248637).

2⁹⁹¹⁶⁷³ is an apocalyptic number.

It is an amenable number.

991673 is a deficient number, since it is larger than the sum of its proper divisors (2875).

991673 is a wasteful number, since it uses less digits than its factorization.

991673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2874.

The product of its digits is 10206, while the sum is 35.

The square root of 991673 is about 995.8277963584. The cubic root of 991673 is about 99.7216593168.

The spelling of 991673 in words is "nine hundred ninety-one thousand, six hundred seventy-three".