1205865 has 24 divisors (see below), whose sum is σ = 2116608. Its totient is φ = 635040.

The previous prime is 1205843. The next prime is 1205891. The reversal of 1205865 is 5685021.

It is not a de Polignac number, because 1205865 - 2⁸ = 1205609 is a prime.

It is a super-2 number, since 2×1205865² = 2908220796450, which contains 22 as substring.

It is an Ulam number.

1205865 is a lucky number.

It is a plaindrome in base 16.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5610 + ... + 5820.

It is an arithmetic number, because the mean of its divisors is an integer number (88192).

2^1205865 is an apocalyptic number.

1205865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1205865 is a deficient number, since it is larger than the sum of its proper divisors (910743).

1205865 is a wasteful number, since it uses less digits than its factorization.

1205865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349 (or 346 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 1205865 is about 1098.1188460272. The cubic root of 1205865 is about 106.4387004244.

The spelling of 1205865 in words is "one million, two hundred five thousand, eight hundred sixty-five".