2123820 has 144 divisors (see below), whose sum is σ = 7338240. Its totient is φ = 513216.

The previous prime is 2123791. The next prime is 2123831. The reversal of 2123820 is 283212.

It is a happy number.

It is a super-2 number, since 2×2123820² = 9021222784800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 2123793 and 2123802.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 92329 + ... + 92351.

It is an arithmetic number, because the mean of its divisors is an integer number (50960).

2^2123820 is an apocalyptic number.

2123820 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 2123820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3669120).

2123820 is an abundant number, since it is smaller than the sum of its proper divisors (5214420).

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

2123820 is a wasteful number, since it uses less digits than its factorization.

2123820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 2123820 is about 1457.3331808478. Note that the first 3 decimals coincide. The cubic root of 2123820 is about 128.5402781677.

The spelling of 2123820 in words is "two million, one hundred twenty-three thousand, eight hundred twenty".