861815 has 8 divisors (see below), whose sum is σ = 1095120. Its totient is φ = 648832.

The previous prime is 861803. The next prime is 861823. The reversal of 861815 is 518168.

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 861815 - 2⁴ = 861799 is a prime.

It is a plaindrome in base 12.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4985 + ... + 5154.

It is an arithmetic number, because the mean of its divisors is an integer number (136890).

2⁸⁶¹⁸¹⁵ is an apocalyptic number.

861815 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

861815 is a deficient number, since it is larger than the sum of its proper divisors (233305).

861815 is a wasteful number, since it uses less digits than its factorization.

861815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10161.

The product of its digits is 1920, while the sum is 29.

The square root of 861815 is about 928.3399161945. The cubic root of 861815 is about 95.1637066537.

The spelling of 861815 in words is "eight hundred sixty-one thousand, eight hundred fifteen".