1812021 has 4 divisors (see below), whose sum is σ = 2416032. Its totient is φ = 1208012.

The previous prime is 1811993. The next prime is 1812037. The reversal of 1812021 is 1202181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1812021 - 2⁷ = 1811893 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1812061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 302001 + ... + 302006.

It is an arithmetic number, because the mean of its divisors is an integer number (604008).

2^1812021 is an apocalyptic number.

It is an amenable number.

1812021 is a deficient number, since it is larger than the sum of its proper divisors (604011).

1812021 is an equidigital number, since it uses as much as digits as its factorization.

1812021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604010.

The product of its (nonzero) digits is 32, while the sum is 15.

The square root of 1812021 is about 1346.1132938947. The cubic root of 1812021 is about 121.9142324713.

The spelling of 1812021 in words is "one million, eight hundred twelve thousand, twenty-one".