2821820 has 24 divisors (see below), whose sum is σ = 5964000. Its totient is φ = 1121472.

The previous prime is 2821817. The next prime is 2821829. The reversal of 2821820 is 281282.

2821820 is nontrivially palindromic in base 9.

It is a super-2 number, since 2×2821820² = 15925336224800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2821829) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3626 + ... + 4334.

It is an arithmetic number, because the mean of its divisors is an integer number (248500).

2^2821820 is an apocalyptic number.

2821820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2821820 is an abundant number, since it is smaller than the sum of its proper divisors (3142180).

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

2821820 is a wasteful number, since it uses less digits than its factorization.

2821820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 917 (or 915 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The square root of 2821820 is about 1679.8273720832. The cubic root of 2821820 is about 141.3111516353.

The spelling of 2821820 in words is "two million, eight hundred twenty-one thousand, eight hundred twenty".