2021816 has 8 divisors (see below), whose sum is σ = 3790920. Its totient is φ = 1010904.

The previous prime is 2021807. The next prime is 2021837. The reversal of 2021816 is 6181202.

It is a tau number, because it is divible by the number of its divisors (8).

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, 126356 + ... + 126371.

It is an arithmetic number, because the mean of its divisors is an integer number (473865).

2^2021816 is an apocalyptic number.

It is an amenable number.

2021816 is a deficient number, since it is larger than the sum of its proper divisors (1769104).

2021816 is a wasteful number, since it uses less digits than its factorization.

2021816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252733 (or 252729 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 2021816 is about 1421.9057634035. The cubic root of 2021816 is about 126.4485566263.

The spelling of 2021816 in words is "two million, twenty-one thousand, eight hundred sixteen".