991967 has 16 divisors (see below), whose sum is σ = 1140480. Its totient is φ = 857472.

The previous prime is 991961. The next prime is 991973. The reversal of 991967 is 769199.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (991961) and next prime (991973).

It is a cyclic number.

It is not a de Polignac number, because 991967 - 2⁴ = 991951 is a prime.

It is a Duffinian number.

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 991967.

It is not an unprimeable number, because it can be changed into a prime (991961) 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, 16784 + ... + 16842.

It is an arithmetic number, because the mean of its divisors is an integer number (71280).

2⁹⁹¹⁹⁶⁷ is an apocalyptic number.

991967 is a deficient number, since it is larger than the sum of its proper divisors (148513).

991967 is a wasteful number, since it uses less digits than its factorization.

991967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142.

The product of its digits is 30618, while the sum is 41.

The square root of 991967 is about 995.9754013027. The cubic root of 991967 is about 99.7315131265.

The spelling of 991967 in words is "nine hundred ninety-one thousand, nine hundred sixty-seven".