991007 has 4 divisors (see below), whose sum is σ = 993840. Its totient is φ = 988176.

The previous prime is 990989. The next prime is 991009. The reversal of 991007 is 700199.

991007 is nontrivially palindromic in base 16.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991007 is a prime.

It is a Duffinian number.

991007 is an undulating number in base 16.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 803 + ... + 1620.

It is an arithmetic number, because the mean of its divisors is an integer number (248460).

2⁹⁹¹⁰⁰⁷ is an apocalyptic number.

991007 is a deficient number, since it is larger than the sum of its proper divisors (2833).

991007 is a wasteful number, since it uses less digits than its factorization.

991007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2832.

The product of its (nonzero) digits is 567, while the sum is 26.

The square root of 991007 is about 995.4933450305. The cubic root of 991007 is about 99.6993302162.

The spelling of 991007 in words is "nine hundred ninety-one thousand, seven".