1821424 has 40 divisors (see below), whose sum is σ = 3928320. Its totient is φ = 811200.

The previous prime is 1821409. The next prime is 1821427. The reversal of 1821424 is 4241281.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a nude number because it is divisible by every one of its digits.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 1821395 and 1821404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13839 + ... + 13969.

It is an arithmetic number, because the mean of its divisors is an integer number (98208).

2^1821424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1821424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1964160).

1821424 is an abundant number, since it is smaller than the sum of its proper divisors (2106896).

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

1821424 is a wasteful number, since it uses less digits than its factorization.

1821424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229 (or 223 counting only the distinct ones).

The product of its digits is 512, while the sum is 22.

The square root of 1821424 is about 1349.6014226430. The cubic root of 1821424 is about 122.1247492214.

The spelling of 1821424 in words is "one million, eight hundred twenty-one thousand, four hundred twenty-four".