991155 has 16 divisors (see below), whose sum is σ = 1730304. Its totient is φ = 480480.

The previous prime is 991147. The next prime is 991171. The reversal of 991155 is 551199.

991155 = T₄₁₉ + T₄₂₀ + ... + T₄₂₉.

It is not a de Polignac number, because 991155 - 2³ = 991147 is a prime.

It is a zygodrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2839 + ... + 3168.

It is an arithmetic number, because the mean of its divisors is an integer number (108144).

2⁹⁹¹¹⁵⁵ is an apocalyptic number.

991155 is a deficient number, since it is larger than the sum of its proper divisors (739149).

991155 is a wasteful number, since it uses less digits than its factorization.

991155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6026.

The product of its digits is 2025, while the sum is 30.

The square root of 991155 is about 995.5676772576. The cubic root of 991155 is about 99.7042931029.

The spelling of 991155 in words is "nine hundred ninety-one thousand, one hundred fifty-five".