2121985 has 4 divisors (see below), whose sum is σ = 2546388. Its totient is φ = 1697584.

The previous prime is 2121979. The next prime is 2121989. The reversal of 2121985 is 5891212.

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 992016 + 1129969 = 996^2 + 1063^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121985 - 2¹¹ = 2119937 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212194 + ... + 212203.

It is an arithmetic number, because the mean of its divisors is an integer number (636597).

2^2121985 is an apocalyptic number.

It is an amenable number.

2121985 is a deficient number, since it is larger than the sum of its proper divisors (424403).

2121985 is an equidigital number, since it uses as much as digits as its factorization.

2121985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424402.

The product of its digits is 1440, while the sum is 28.

The square root of 2121985 is about 1456.7034701682. The cubic root of 2121985 is about 128.5032475068.

It can be divided in two parts, 212 and 1985, that added together give a cube (2197 = 13³).

The spelling of 2121985 in words is "two million, one hundred twenty-one thousand, nine hundred eighty-five".