991145 has 8 divisors (see below), whose sum is σ = 1197504. Its totient is φ = 787504.

The previous prime is 991129. The next prime is 991147. The reversal of 991145 is 541199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 991145 - 2⁴ = 991129 is a prime.

It is a super-2 number, since 2×991145² = 1964736822050, which contains 22 as substring.

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 991145.

It is not an unprimeable number, because it can be changed into a prime (991147) 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 7 ways as a sum of consecutive naturals, for example, 242 + ... + 1428.

It is an arithmetic number, because the mean of its divisors is an integer number (149688).

2⁹⁹¹¹⁴⁵ is an apocalyptic number.

It is an amenable number.

991145 is a deficient number, since it is larger than the sum of its proper divisors (206359).

991145 is a wasteful number, since it uses less digits than its factorization.

991145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1359.

The product of its digits is 1620, while the sum is 29.

The square root of 991145 is about 995.5626549846. The cubic root of 991145 is about 99.7039577883.

The spelling of 991145 in words is "nine hundred ninety-one thousand, one hundred forty-five".