991079 has 2 divisors, whose sum is σ = 991080. Its totient is φ = 991078.

The previous prime is 991073. The next prime is 991091. The reversal of 991079 is 970199.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991079 - 2⁴ = 991063 is a prime.

It is a Sophie Germain prime.

It is equal to p₇₇₈₅₈ and since 991079 and 77858 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495539 + 495540.

It is an arithmetic number, because the mean of its divisors is an integer number (495540).

2⁹⁹¹⁰⁷⁹ is an apocalyptic number.

991079 is a deficient number, since it is larger than the sum of its proper divisors (1).

991079 is an equidigital number, since it uses as much as digits as its factorization.

991079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5103, while the sum is 35.

The square root of 991079 is about 995.5295073477. The cubic root of 991079 is about 99.7017446552.

The spelling of 991079 in words is "nine hundred ninety-one thousand, seventy-nine".