2021540 has 24 divisors (see below), whose sum is σ = 4317432. Its totient is φ = 794880.

The previous prime is 2021533. The next prime is 2021549. The reversal of 2021540 is 451202.

It can be written as a sum of positive squares in 4 ways, for example, as 10816 + 2010724 = 104^2 + 1418^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (2021549) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 392 + ... + 2048.

It is an arithmetic number, because the mean of its divisors is an integer number (179893).

2^2021540 is an apocalyptic number.

2021540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2021540 is an abundant number, since it is smaller than the sum of its proper divisors (2295892).

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

2021540 is a wasteful number, since it uses less digits than its factorization.

2021540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1727 (or 1725 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 14.

The square root of 2021540 is about 1421.8087072458. The cubic root of 2021540 is about 126.4428024941.

Adding to 2021540 its reverse (451202), we get a palindrome (2472742).

The spelling of 2021540 in words is "two million, twenty-one thousand, five hundred forty".