1213865 has 4 divisors (see below), whose sum is σ = 1456644. Its totient is φ = 971088.

The previous prime is 1213841. The next prime is 1213873. The reversal of 1213865 is 5683121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 652864 + 561001 = 808^2 + 749^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213865 - 2⁶ = 1213801 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121382 + ... + 121391.

It is an arithmetic number, because the mean of its divisors is an integer number (364161).

2^1213865 is an apocalyptic number.

It is an amenable number.

1213865 is a deficient number, since it is larger than the sum of its proper divisors (242779).

1213865 is an equidigital number, since it uses as much as digits as its factorization.

1213865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242778.

The product of its digits is 1440, while the sum is 26.

The square root of 1213865 is about 1101.7554175043. The cubic root of 1213865 is about 106.6735618373.

Adding to 1213865 its reverse (5683121), we get a palindrome (6896986).

The spelling of 1213865 in words is "one million, two hundred thirteen thousand, eight hundred sixty-five".