1818421 has 4 divisors (see below), whose sum is σ = 1983744. Its totient is φ = 1653100.

The previous prime is 1818419. The next prime is 1818431. The reversal of 1818421 is 1248181.

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 1818421 - 2¹ = 1818419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1818431) 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, 82645 + ... + 82666.

It is an arithmetic number, because the mean of its divisors is an integer number (495936).

2^1818421 is an apocalyptic number.

1818421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1818421 is a deficient number, since it is larger than the sum of its proper divisors (165323).

1818421 is a wasteful number, since it uses less digits than its factorization.

1818421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165322.

The product of its digits is 512, while the sum is 25.

The square root of 1818421 is about 1348.4884130018. The cubic root of 1818421 is about 122.0575962033.

The spelling of 1818421 in words is "one million, eight hundred eighteen thousand, four hundred twenty-one".