1821816 has 24 divisors (see below), whose sum is σ = 4934280. Its totient is φ = 607248.

The previous prime is 1821791. The next prime is 1821821. The reversal of 1821816 is 6181281.

It is a tau number, because it is divible by the number of its divisors (24).

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

It is a self number, because there is not a number n which added to its sum of digits gives 1821816.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12580 + ... + 12723.

It is an arithmetic number, because the mean of its divisors is an integer number (205595).

2^1821816 is an apocalyptic number.

It is an amenable number.

1821816 is an abundant number, since it is smaller than the sum of its proper divisors (3112464).

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

1821816 is a wasteful number, since it uses less digits than its factorization.

1821816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25315 (or 25308 counting only the distinct ones).

The product of its digits is 768, while the sum is 27.

The square root of 1821816 is about 1349.7466428927. The cubic root of 1821816 is about 122.1335096688.

The spelling of 1821816 in words is "one million, eight hundred twenty-one thousand, eight hundred sixteen".