2801820 has 72 divisors (see below), whose sum is σ = 9135504. Its totient is φ = 639744.

The previous prime is 2801819. The next prime is 2801833. The reversal of 2801820 is 281082.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2464 + ... + 3416.

It is an arithmetic number, because the mean of its divisors is an integer number (126882).

2^2801820 is an apocalyptic number.

2801820 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 2801820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4567752).

2801820 is an abundant number, since it is smaller than the sum of its proper divisors (6333684).

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

2801820 is a wasteful number, since it uses less digits than its factorization.

2801820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 979 (or 970 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

The square root of 2801820 is about 1673.8637937419. The cubic root of 2801820 is about 140.9765063216.

The spelling of 2801820 in words is "two million, eight hundred one thousand, eight hundred twenty".