2020644 has 54 divisors (see below), whose sum is σ = 5377554. Its totient is φ = 639360.

The previous prime is 2020621. The next prime is 2020657. The reversal of 2020644 is 4460202.

2020644 is a `hidden beast` number, since 2 + 0 + 20 + 644 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 580644 + 1440000 = 762^2 + 1200^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent 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 17 ways as a sum of consecutive naturals, for example, 49264 + ... + 49304.

2^2020644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2020644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2688777).

2020644 is an abundant number, since it is smaller than the sum of its proper divisors (3356910).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2020644 is a wasteful number, since it uses less digits than its factorization.

2020644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 83 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 2020644 is about 1421.4935807101. The cubic root of 2020644 is about 126.4241188019.

Adding to 2020644 its reverse (4460202), we get a palindrome (6480846).

The spelling of 2020644 in words is "two million, twenty thousand, six hundred forty-four".