2251820 has 48 divisors (see below), whose sum is σ = 5171040. Its totient is φ = 820224.

The previous prime is 2251819. The next prime is 2251829. The reversal of 2251820 is 281522.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 2251792 and 2251801.

It is not an unprimeable number, because it can be changed into a prime (2251829) 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, 12491 + ... + 12669.

It is an arithmetic number, because the mean of its divisors is an integer number (107730).

2^2251820 is an apocalyptic number.

2251820 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 2251820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2585520).

2251820 is an abundant number, since it is smaller than the sum of its proper divisors (2919220).

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

2251820 is a wasteful number, since it uses less digits than its factorization.

2251820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 2251820 is about 1500.6065440348. The cubic root of 2251820 is about 131.0723916649.

The spelling of 2251820 in words is "two million, two hundred fifty-one thousand, eight hundred twenty".