991073 has 2 divisors, whose sum is σ = 991074. Its totient is φ = 991072.

The previous prime is 991069. The next prime is 991079. The reversal of 991073 is 370199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 786769 + 204304 = 887^2 + 452^2 .

It is an emirp because it is prime and its reverse (370199) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 991073 - 2² = 991069 is a prime.

It is not a weakly prime, because it can be changed into another prime (991079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495536 + 495537.

It is an arithmetic number, because the mean of its divisors is an integer number (495537).

2⁹⁹¹⁰⁷³ is an apocalyptic number.

It is an amenable number.

991073 is a deficient number, since it is larger than the sum of its proper divisors (1).

991073 is an equidigital number, since it uses as much as digits as its factorization.

991073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1701, while the sum is 29.

The square root of 991073 is about 995.5264938715. The cubic root of 991073 is about 99.7015434564.

The spelling of 991073 in words is "nine hundred ninety-one thousand, seventy-three".