2021686 has 4 divisors (see below), whose sum is σ = 3032532. Its totient is φ = 1010842.

The previous prime is 2021671. The next prime is 2021693. The reversal of 2021686 is 6861202.

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

It is a self number, because there is not a number n which added to its sum of digits gives 2021686.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 505420 + ... + 505423.

It is an arithmetic number, because the mean of its divisors is an integer number (758133).

2^2021686 is an apocalyptic number.

2021686 is a deficient number, since it is larger than the sum of its proper divisors (1010846).

2021686 is a wasteful number, since it uses less digits than its factorization.

2021686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1010845.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 2021686 is about 1421.8600493719. The cubic root of 2021686 is about 126.4458464119.

Adding to 2021686 its reverse (6861202), we get a palindrome (8882888).

It can be divided in two parts, 20216 and 86, that added together give a palindrome (20302).

The spelling of 2021686 in words is "two million, twenty-one thousand, six hundred eighty-six".