1215985 has 4 divisors (see below), whose sum is σ = 1459188. Its totient is φ = 972784.

The previous prime is 1215923. The next prime is 1216009. The reversal of 1215985 is 5895121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5895121 = 367 ⋅16063.

It can be written as a sum of positive squares in 2 ways, for example, as 876096 + 339889 = 936^2 + 583^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215985 - 2¹⁹ = 691697 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

1215985 is a lucky number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 121594 + ... + 121603.

It is an arithmetic number, because the mean of its divisors is an integer number (364797).

2^1215985 is an apocalyptic number.

It is an amenable number.

1215985 is a deficient number, since it is larger than the sum of its proper divisors (243203).

1215985 is an equidigital number, since it uses as much as digits as its factorization.

1215985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243202.

The product of its digits is 3600, while the sum is 31.

The square root of 1215985 is about 1102.7170988064. The cubic root of 1215985 is about 106.7356270652.

The spelling of 1215985 in words is "one million, two hundred fifteen thousand, nine hundred eighty-five".