861099 has 8 divisors (see below), whose sum is σ = 1208640. Its totient is φ = 543816.

The previous prime is 861089. The next prime is 861109. The reversal of 861099 is 990168.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (861089) and next prime (861109).

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

It is not a de Polignac number, because 861099 - 2⁴ = 861083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (861019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7497 + ... + 7610.

It is an arithmetic number, because the mean of its divisors is an integer number (151080).

2⁸⁶¹⁰⁹⁹ is an apocalyptic number.

861099 is a deficient number, since it is larger than the sum of its proper divisors (347541).

861099 is a wasteful number, since it uses less digits than its factorization.

861099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15129.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 861099 is about 927.9542014561. The cubic root of 861099 is about 95.1373451987.

The spelling of 861099 in words is "eight hundred sixty-one thousand, ninety-nine".