1811421 has 12 divisors (see below), whose sum is σ = 2680860. Its totient is φ = 1177920.

The previous prime is 1811413. The next prime is 1811431. The reversal of 1811421 is 1241181.

It can be written as a sum of positive squares in 2 ways, for example, as 1028196 + 783225 = 1014^2 + 885^2 .

It is not a de Polignac number, because 1811421 - 2³ = 1811413 is a prime.

1811421 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1811394 and 1811403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1811431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2086 + ... + 2823.

It is an arithmetic number, because the mean of its divisors is an integer number (223405).

2^1811421 is an apocalyptic number.

It is an amenable number.

1811421 is a deficient number, since it is larger than the sum of its proper divisors (869439).

1811421 is a wasteful number, since it uses less digits than its factorization.

1811421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4956 (or 4953 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

The square root of 1811421 is about 1345.8904115863. The cubic root of 1811421 is about 121.9007748247.

The spelling of 1811421 in words is "one million, eight hundred eleven thousand, four hundred twenty-one".