1223820 has 72 divisors (see below), whose sum is σ = 4005456. Its totient is φ = 300672.

The previous prime is 1223777. The next prime is 1223857. The reversal of 1223820 is 283221.

It is a happy number.

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 = 1223793 and 1223802.

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, 2079 + ... + 2601.

2^1223820 is an apocalyptic number.

1223820 is a gapful number since it is divisible by the number (10) 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 1223820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2002728).

1223820 is an abundant number, since it is smaller than the sum of its proper divisors (2781636).

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

1223820 is a wasteful number, since it uses less digits than its factorization.

1223820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551 (or 546 counting only the distinct ones).

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

The square root of 1223820 is about 1106.2639829625. The cubic root of 1223820 is about 106.9643809587.

It can be divided in two parts, 12 and 23820, that added together give a palindrome (23832).

The spelling of 1223820 in words is "one million, two hundred twenty-three thousand, eight hundred twenty".