2809820 has 48 divisors (see below), whose sum is σ = 6477408. Its totient is φ = 1017600.

The previous prime is 2809813. The next prime is 2809823. The reversal of 2809820 is 289082.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2809823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26207 + ... + 26313.

It is an arithmetic number, because the mean of its divisors is an integer number (134946).

2^2809820 is an apocalyptic number.

2809820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2809820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3238704).

2809820 is an abundant number, since it is smaller than the sum of its proper divisors (3667588).

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

2809820 is a wasteful number, since it uses less digits than its factorization.

2809820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 228 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 2809820 is about 1676.2517710654. The cubic root of 2809820 is about 141.1105549448.

The spelling of 2809820 in words is "two million, eight hundred nine thousand, eight hundred twenty".